Maclean et al. - 2002 - Rice almanac source book for the most important e


Maclean et al. - 2002 - Rice almanac source book for the most important e

Third Edition

Source Book for the Most Important

Economic Activity on Earth

Edited by J.L. Maclean, D.C. Dawe, B. Hardy, and G.P. Hettel




CABI Publishing Tel: Wallingford +44 (0)1491 832111

A Division of CAB International Fax: +44 (0)1491 833508

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Published in association with:

International Rice Research Institute

DAPO Box 7777, Metro Manila, Philippines

West Africa Rice Development Association

01 B.P. 2551, Bouaké 01, Côte d’Ivoire

International Center for Tropical Agriculture

Food and Agriculture Organization

Apartado Aéreo 6713, Cali, Colombia of the United Nations

Via delle Terme di Caracalla, Rome, Italy

© International Rice Research Institute 2002

The International Rice Research Institute (IRRI), the West Africa Rice Development Association (WARDA),

and the International Center for Tropical Agriculture (CIAT, its Spanish acronym) are three of 16 Future

Harvest research centers funded by the Consultative Group on International Agricultural Research

(CGIAR). The CGIAR is cosponsored by the Food and Agriculture Organization of the United Nations

(FAO), the International Bank for Reconstruction and Development (World Bank), the United Nations

Development Programme, and the United Nations Environment Programme. Its membership comprises

donor countries, international and regional organizations, and private foundations. Its mission is to

contribute to food security and poverty eradication in developing countries through research,

partnerships, capacity building, and policy support, promoting sustainable agricultural development

based on the environmentally sound management of natural resources. FAO is the United Nations

agency that leads international efforts to defeat hunger and works to help developing countries

modernize and expand agriculture, forestry, and fisheries and ensure good nutrition for all.

Responsibility for this publication rests with IRRI. The designations employed in the presentation of the

material in this publication do not imply the expression of any opinion whatsoever on the part of IRRI,

WARDA, CIAT, FAO, or CABI concerning the legal status of any country, territory, city, or area, or of its

authorities, or the delimitation of its frontiers or boundaries.

Catalog entries for this book are available from the British Library, London, UK, and from the Library of

Congress, Washington, DC, USA.

ISBN 0 85199 636 1

Cover photo: Rice terraces in eastern Bhutan (Gene Hettel).

Typeset, printed, and bound in China.


Foreword v

Acknowledgments vi

The facts of rice vii


Origin and diffusion 1

Genetic diversity 2

Rice-growing areas 4

Production 4

Rice as human food 6

Rice and population 8

Specialty uses of rice 8


Morphology 11

Growth 13

Soils 14

Environments 16

Rice ecosystems 16

Enemies and friends 24


The looming water crisis 31

Aerobic rice 32

Adding protein, vitamin A,

and other micronutrients 33

Increasing yield potential 34

Functional genomics 36

Global climate change and rice 37

Emissions of greenhouse gases

from rice fields 38

Biotechnology issues 40

Crop modeling to integrate

knowledge 43



International Rice Research

Institute (IRRI) 46

West Africa Rice Development

Association (WARDA) 50

Centro Internacional de Agricultura

Tropical (CIAT) 55

FAO 58


Introduction 59

Rice and food security in Asia 61

Rice in Europe and the

Mediterranean 68

Rice in North America 72

Rice in Latin America and

the Caribbean 76

Rice in West Africa 79

The top 10 rice-producing countries 85

China 86

India 90

Indonesia 94

Bangladesh 98

Vietnam 102

Thailand 106

Myanmar 110

Japan 114

Philippines 118

Brazil 122

Rice in 54 other countries 127

Afghanistan 128

Argentina 130


Australia 132

Bhutan 134

Bolivia 136

Burkina Faso 138

Cambodia 140

Cameroon 142

Chad, Republic of 144

Colombia 146

Congo, Democratic

Republic of the 148

Côte d’Ivoire 150

Cuba 152

Dominican Republic 154

Ecuador 156

Egypt 158

France 160

Gambia, The 162

Ghana, Republic of 164

Greece 166

Guinea 168

Guinea Bissau 170

Guyana 172

Iran 174

Italy 176

Korea DPR 178

Korea, Republic of 180

Lao PDR 182

Liberia 184

Madagascar 186

Malaysia 188

Mali 190

Mauritania 192

Mexico 194

Mozambique 196

Nepal 198

Nicaragua 200

Niger 202

Nigeria 204

Pakistan 206

Paraguay 208

Peru 210

Portugal 212

Russian Federation 214

Senegal 216

Sierra Leone 218

Spain 220

Sri Lanka 222

Suriname 224

Tanzania 226

Turkey 228

USA 230

Uruguay 232

Venezuela 234

Rice-related databases 236

Important conversion factors,

by country 245

Rice facts 249



The first edition of the Rice Almanac was

published in 1993 in response to the long-felt

need to bring together general information about

rice—its origin, its growth and production, the

ecosystems under which it is grown, and

opportunities for increased yields.

A second edition was published in 1997,

incorporating much updated material on

production and geographical data plus new

information on a number of countries as well as

regional information on West African countries

from the West Africa Rice Development

Association (WARDA) in Côte d’Ivoire, on the

Latin American and Caribbean region and

countries from the Centro Internacional de

Agricultura Tropical (CIAT) in Colombia, and on

European rice production. WARDA and CIAT

became copublishers of the second edition with


The second edition also gave rise to an

Internet site, Riceweb (, which

contains all the Almanac contents as well as a

host of additional information about rice, such as

rice testing protocols, recipes, a glossary of rice

terminology, and access to rice literature and

many other rice-related Web sites from around

the world. Riceweb has become a highly visited

site, earning acclaim also from several Web-site

rating and other organizations, such as the Dow

Jones Business Directory, New Scientist, Natural

Selection, and USA Today.

For the third edition, we have doubled the

number of countries for which production-related

information is provided. This is due to help from

the Food and Agriculture Organization of the

United Nations (FAO), which agreed to provide

material from its rice production country

database (CORIFA—country rice facts) and to

become a copublisher of the Almanac. The

Almanac now covers 64 countries, including all

the major producers.

The production and other statistics used

herein are derived primarily from FAO, which

include official country data (FAOSTAT),

surveys, reports, and personal communications;

IRRI’s RICESTAT database, which is based on

primary data from requests and questionnaires

and secondary data from statistical publications

and international organizations including FAO,

the International Labour Organization, the World

Bank, etc.; and regional data from CIAT and


We thank CABI, which has worked with us

in producing a copublished hardcover version for

distribution in developed countries.

We trust that the third edition of the Rice

Almanac will continue to increase awareness of

rice as the most important staple food in the

world and of all that is involved in maintaining

rice production.

Ronald P. Cantrell

Director General, IRRI



The third edition of the Almanac builds on

contributions to the first two editions by many

people both within IRRI and around the world.

Those who contributed to the third edition


Contributors of chapters or sections: Lee

Calvert and Luis Sanint (CIAT), Mahabub

Hossain (IRRI), Aldo Ferrero (Italy), Tom

Hargrove (USA), Ryoichi Ikeda (Japan), Marco

Wopereis and Guy Manners [coordinator]

(WARDA), and Nguu Nguyen (FAO).

Reviewers from IRRI: Gary Atlin, Alberto

Barrion, Mark Bell, Roland Buresh, Mike Cohen,

Hiroyuku Hibino, James Hill, Guy Kirk, Hei

Leung, Duncan Macintosh, David Mackill,

Graham McLaren, M.A. Hamid Miah, Josephine

Narciso, Shaobing Peng, Mila Ramos, John

Sheehy, Virendra Pal Singh, Boriboon Somrith,

Mahyuddin Syam, Shengxiang Tang, To Phuc

Tuong, Shiela Valencia, Sant Virmani, Len Wade,

and Ren Wang.

External reviewers: B.N. Singh, Director

General, Central Rice Research Institute (India),

N.I. Bhuiyan, Aung Kyi, and U Tin Htut Oo,

Director General, Department of Agricultural

Planning (Myanmar); Leo Sebastian, Director

General, PhilRice (Philippines); Somporn

Isvilanonda, Kasetsart University (Thailand); and

Bui Chi Buu, Director, Cuu Long Rice Research

Institute (Vietnam).

IRRI production team: Grant Leceta (design

and layout), Emmanuel Panisales and Ana Mae

Wenceslao (figures and maps), and Juan Lazaro

IV (cover).

The publishers wish to thank all these

people—and those whose names we may have

missed—for their time and effort to ensure the

accuracy and usefulness of the Almanac.


The facts of rice


Rice farming is the largest single use of land for

producing food.

Rice is nearly all (90%) produced in Asia.

Rice production totaled 600 million tons in 2000.

Rice is the most important economic activity on


Thousands of varieties of rice are farmed.

Only 6–7% of all rice production is

exported from its country of origin.

Rice fields cover 9% of Earth’s entire

arable land, or more than 125 million hectares.


Rice eaters and growers form the bulk of the

world’s poor.

Rice is the single most important source of

employment and income for rural people.

Rice is grown on 250 million Asian farms,

mostly smaller than one hectare.

Significance in human culture

Rice farming is about 10,000 years old.

Rice cultivation was once the basis of the social

order and occupied a major place in Asia’s

religions and customs.

Rice is still sometimes used to pay debts,

wages, and rent in some Asian rural areas.

Significance as food

Rice is the staple food for the largest number of

people on Earth.

Rice is eaten by nearly half the world’s


Rice is the single largest food source for the


Rice is the source of one quarter of global per

capita energy.

Rice is synonymous with food throughout Asia.

Rice is the most important food grain in most of

the tropical areas of Latin America and the

Caribbean, where it supplies more calories in

people’s diets than wheat, maize, cassava, or


Toyota means bountiful rice field.

Honda means the main rice field.

Benefits of rice research

Research has provided 75% of the rice varieties

now grown.

Research has increased potential yields from 4

to more than 10 tonnes per hectare per crop.

Research has been a major factor in more than

doubling world rice production from 260 to

600 million tonnes over the past 40 years.

Research has provided rice plants that grow

faster, enabling 2 or even 3 crops per year;

plants that resist various pests and diseases,

need less fertilizer, or thrive in saline water;

and plants with enhanced levels of


Many more facts on rice production are contained in the

Rice Facts on page 249.


Importance of rice

Origin and diffusion

The origins of rice have long been debated.

The plant is of such antiquity that the

exact time and place of its first

development will perhaps never be known. It is

certain, however, that domestication of rice ranks

as one of the most important developments in

history. Rice has fed more people over a longer

period than has any other crop.

Pottery shards bearing the imprint of both

grains and husks of the cultivated rice species

Oryza sativa were discovered at Non Nok Tha in

the Korat area of Thailand. Plant remains from

10000 B.C. were discovered in Spirit Cave on

the Thailand-Myanmar border.

In China, extensive archeological evidence

points to the middle Yangtze and upper Huai

rivers as the two earliest places of O. sativa rice

cultivation in the country. Rice and farming

implements dating back at least 8,000 years have

been found. Cultivation spread down these rivers

over the following 2,000 years.

Early spread of rice

From early, perhaps separate, beginnings in

different parts of Asia, the process of diffusion

has carried rice in all directions until today it is

cultivated on every continent save Antarctica. In

the early Neolithic era, rice was grown in forest

clearings under a system of shifting cultivation.

The crop was direct seeded, without standing

water—conditions only slightly different from

those to which wild rice was subject. A similar

but independent pattern of the incorporation of

wild rice into agricultural systems may well have

taken place in one or more locations in Africa at

approximately the same time.

Puddling the soil—turning it to mud—and

transplanting seedlings were likely refined in

China. Both operations became integral parts of

rice farming and remain widely practiced to this

day. Puddling breaks down the internal structure

of soils, making them much less subject to water

loss through percolation. In this respect, it can be

thought of as a way to extend the utility of a limited

water supply.

Banaue Rice Terraces, Philippines.

Importance of rice 1

Transplanting is the planting of 1- to 6-wkold

seedlings in puddled soil with standing water.

Under these conditions, the rice plants have an

important head start over a wide range of competing

weeds, which leads to higher yields.

Transplanting, like puddling, provides farmers

with the ability to better accommodate the rice

crop to a finite and fickle water supply by shortening

the field duration (since seedlings are

grown separately and at higher density) and

adjusting the planting calendar.

With the development of puddling and transplanting,

rice became truly domesticated. In

China, the history of rice in river valleys and

low-lying areas is longer than its history as a

dryland crop. In Southeast Asia, however, rice

originally was produced under dryland

conditions in the uplands, and only recently

came to occupy the vast river deltas.

Migrant people from southern China or perhaps

northern Vietnam carried the traditions of

wetland rice cultivation to the Philippines during

the second millennium B.C., and Deutero-

Malays carried the practice to Indonesia about

1500 B.C. From China or Korea, the crop was

introduced to Japan no later than 100 B.C.

Movement to western India and south to Sri

Lanka was also accomplished very early. Rice

was a major crop in Sri Lanka as early as 1000

B.C. The crop may well have been introduced to

Greece and the neighboring areas of the

Mediterranean by returning members of

Alexander the Great’s expedition to India around

344-324 B.C. From a center in Greece and Sicily,

rice spread gradually throughout southern

Europe and to a few locations in northern Africa.

Rice in the New World

As a result of Europe’s great Age of Exploration,

new lands to the west became available for exploitation.

Rice cultivation was introduced to the

New World by early European settlers. The Portuguese

carried it to Brazil and the Spanish introduced

its cultivation to several locations in Central

and South America. The first record for

North America dates from 1685, when the crop

was produced on the coastal lowlands and

islands of what is now South Carolina. The crop

may well have been carried to that area by slaves

brought from the African continent. Early in the

18th century, rice spread to what is now

Louisiana, but not until the 20th century was it

produced in California’s Sacramento Valley. The

introduction into California corresponded almost

exactly with the timing of the first successful

crop in Australia’s New South Wales.

Genetic diversity

Two rice species are important cereals for human

nutrition: Oryza sativa, grown worldwide, and O.

glaberrima, grown in parts of West Africa. These

two cultigens—species known only by cultivated

plants—belong to a genus that includes about 20

other species.

Wild Oryza species are distributed throughout

the tropics. They can be grouped into four

complexes of closely related species (Table 1).

Two species, however, seem to be different from

others in the genus: the tetraploid O. schlechteri

and the diploid O. brachyantha.

Species of the O. ridleyi complex inhabit

lowland swamp forests and species of the O.

meyeriana complex are found in upland hillside


The O. officinalis complex consists of

diploid and tetraploid species found throughout

the tropics. All the species in this complex are

perennial; some are rhizomatous and others form

runners. They also differ in the habitats where

they are found. Some occur in full sun, others in

partial shade. Variation exists within these species

as shown by the responses of different

populations to pests and diseases.

The O. sativa complex consists of the wild

and weedy relatives of the two rice cultigens as

well as the cultigens themselves. The wild

relatives of O. glaberrima in Africa consist of the

perennial rhizomatous species O. longistaminata,

which grows throughout Sub-Saharan Africa, and

Madagascar, and the annual O. barthii, which

extends from West Africa to East and Southern

Central Africa. The annual and weedy relatives

of O. glaberrima are found primarily in West


Among the wild relatives of O. sativa, the

perennial O. rufipogon is widely distributed over

South and Southeast Asia, southeast China, and

Oceania; morphologically indistinguishable

forms are found in South America, usually in

deepwater swamps. A closely related annual wild

form, O. nivara, is found in the Deccan Plateau

and Indo-Gangetic Plain of India and in many

parts of Southeast Asia. The habitats of O. nivara

are ditches, water holes, and edges of ponds.

Morphologically similar to (and sometimes in-

2 Rice almanac

Table 1. Taxa in the genus Oryza: the complexes and

genome groups to which they belong.

Complex/taxon Genome group Distribution

O. schlechteri Tetraploid Papua New


O. brachyantha FF Africa

O. ridleyi complex

O. longiglumis Tetraploid Papua New


O. ridleyi Tetraploid Southeast Asia

O. meyeriana complex

O. granulata Diploid South and

Southeast Asia

O. meyeriana Diploid Southeast Asia

O. officinalis complex

O. officinalis CC Tropical Asia

to Papua New


O. eichingeri CC East and West


O. rhizomatis CC Sri Lanka

O. minuta BBCC Philippines,

Papua New


O. punctata BB, BBCC Africa

O. latifolia CCDD Central and

South America

O. alta CCDD Central and

South America

O. grandiglumis CCDD South America

O. australiensis EE Australia

O. sativa complex

O. glaberrima AA West Africa


O. barthii AA Africa

O. longistaminata AA Africa

O. sativa AA Worldwide


O. nivara AA Tropical Asia

O. rufipogon AA Tropical Asia

O. meridionalis AA Tropical


O. glumaepatula AA South America

distinguishable from) O. nivara are the very

widely distributed weedy forms of O. sativa (O.

fatua), which represent numerous different

hybrids between O. sativa and its two wild

relatives. Throughout South and Southeast Asia,

these spontaneous forms are found in canals and

ponds adjacent to rice fields and in the rice fields


The primary center of diversity for O.

glaberrima is in the swampy basin of the upper

Niger River. Two secondary centers are to the

southwest near the Guinean coast.

Oryza glaberrima varieties can be divided

into two ecotypes: deepwater and upland. In

West Africa, O. glaberrima is a dominant crop

grown in the flooded areas of the Niger and

Sokoto River basins. It is broadcast on hoed

fields. On shallowly flooded land, a rainfed

wetland crop is either directly sown by

broadcasting or dibbling, or transplanted. About

45% of the land planted to rice in Africa belongs

to the upland (dryland) culture, largely under

bush fallow or after the ground has been hoed.

Some African farmers still use axes, hoes, and

bush knives in land preparation. In hydromorphic

soils, O. glaberrima behaves like a selfperpetuating

weed. In wetland fields planted to

O. sativa, O. glaberrima has become a weed.

Ecological diversification in O. sativa,

which involved hybridization-differentiationselection

cycles, was enhanced when ancestral

forms of the cultigen were carried by farmers

and traders to higher latitudes, higher elevations,

dryland sites, seasonal deepwater areas, and tidal

swamps. Within broad geographic regions, two

major ecogeographic races were differentiated as

a result of isolation and selection: (1) indica,

adapted to the tropics; and (2) japonica, adapted

to the temperate regions and tropical uplands.

The combined forces of natural and human

selection; diverse climates, seasons, and soils;

and varied cultural practices (dryland preparation

and direct seeding vs puddling of the soil and

transplanting) led to the tremendous ecological

diversity now found in Asian cultivars.

Selections made to suit cultural preferences and

socioreligious traditions added diversity to

morphological features, especially grain size,

shape, and color, and endosperm properties.

The complex groups of cultivars now known

are categorized on the basis of hydrologicedaphic-cultural-seasonal

regimes as well as

genetic differentiation (Fig. 1).

Within the last 2,000 years, dispersal and

cultivation of the cultivars in new habitats have

further accelerated the diversification process.

Today, thousands of rice varieties are grown in

more than 100 countries.

The full spectrum of germplasm in the genus

Oryza consists of the following:

• Wild Oryza species, which occur

throughout the tropics, and related

genera, which occur worldwide in both

temperate and tropical regions.

Importance of rice 3





• Natural hybrids between the cultigen and

wild relatives, and primitive cultivars of

the cultigen in areas of rice diversity.

• Commercial types, obsolete varieties,

minor varieties, and special-purpose types

in the centers of cultivation.

• Pure-line or inbred selections of farmers’

varieties, elite varieties of hybrid origin,

F 1

hybrids, breeding materials, mutants,

polyploids, aneuploids, intergeneric and

interspecific hybrids, composites, and

cytoplasmic sources from breeding


The diversity of Asian, African, and wild

rice has given breeders a wealth of genetic

material to draw on for breeding improved


Rice-growing areas



upland (dryland)

aus (summer)

boro (winter)


aman (autumn)

cereh, hsien, others


(broadcast aman)


lowland (bulu)





0 0.1 1 5

Water depth (m)

Fig. 1. Grouping of Asian rice cultivars by

ecogeographic race, hydrologic-edaphic-cultural

regime, and crop season. Cultivars grown in

standing water belong to the lowland type.

Rice is produced in a wide range of locations and

under a variety of climatic conditions, from the

wettest areas in the world to the driest deserts. It

is produced along Myanmar’s Arakan Coast,

where the growing season records an average of

more than 5,100 mm of rainfall, and at Al Hasa

Oasis in Saudi Arabia, where annual rainfall is

less than 100 mm. Temperatures, too, vary

greatly. In the Upper Sind in Pakistan, the rice

season averages 33 °C; in Otaru, Japan, the mean

temperature for the growing season is 17 °C. The

crop is produced at sea level on coastal plains

and in delta regions throughout Asia, and to a

height of 2,600 m on the slopes of Nepal’s

Himalaya. Rice is also grown under an extremely

broad range of solar radiation, ranging from 25%

of potential during the main rice season in

portions of Myanmar, Thailand, and India’s

Assam State to approximately 95% of potential

in southern Egypt and Sudan.

Rice occupies an extraordinarily high

portion of the total planted area in South,

Southeast, and East Asia. This area is subject to

an alternating wet and dry seasonal cycle and

also contains many of the world’s major rivers,

each with its own vast delta. Here, enormous

areas of flat, low-lying agricultural land are

flooded annually during and immediately

following the rainy season. Only two major food

crops, rice and taro, adapt readily to production

under these conditions of saturated soil and high


The highest rice yields have traditionally

been obtained from plantings in high-latitude

areas that have long daylength and where

intensive farming techniques are practiced, or in

low-latitude desert areas that have very high

solar energy levels. Southwestern Australia,

Hokkaido in Japan, Spain, Italy, northern

California, and the Nile Delta provide the best


In portions of the rice world such as in

South Asia, the crop is produced on miniscule

plots using enormous amounts of human labor.

At other locations, such as in Australia and the

United States, it is raised on huge holdings with

a maximum of technology and large expenditures

of energy from fossil fuels. The contrasts in the

geographic, economic, and social conditions under

which rice is produced are truly remarkable.


Among low- and middle-income countries, rice

is by far the most important crop worldwide. In

particular, rice is most closely associated with

the South, Southeast, and East Asian nations

extending from Pakistan to Japan. Here, the

population pressure on limited land resources is

high and a close balance is maintained between

rice production and food needs. Within this area,

rice is preeminent: it occupies more than onethird

of total planted area in most countries and

4 Rice almanac

Table 2. Rice production, area, and yield for countries producing more than 1 million t of rough rice, in order of

decreasing rough rice production, 2000.

Rough rice Rice area Arable land a % of world rice

Country production (000 ha) (000 ha) Rice yield

(000 t) Area Production (t/ha)

China 190,168 30,503 124,144 20 31.8 6.23

India 134,150 44,600 161,500 29 22.4 3.01

Indonesia 51,000 11,523 17,941 7 8.5 4.43

Bangladesh 35,821 10,700 7,992 7 6.0 3.35

Vietnam 32,554 7,655 5,700 5 5.4 4.25

Thailand 23,403 10,048 16,800 7 3.9 2.33

Myanmar b 20,125 6,211 9,548 4 3.4 3.24

Philippines 12,415 4,037 5,500 3 2.1 3.08

Japan 11,863 1,770 4,535 1 2.0 6.70

Brazil 11,168 3,672 53,200 2 1.9 3.04

USA 8,669 1,232 176,950 1 1.4 7.04

Korea, Rep. of7,067 1,072 1,708 1 1.2 6.59

Pakistan 7,000 2,312 21,425 2 1.2 3.03

Egypt 5,997 660 2,834 0 1.0 9.09

Nepal 4,030 1,550 2,898 1 0.7 2.60

Cambodia 3,762 1,873 3,700 1 0.6 2.01

Nigeria 3,277 2,061 28,200 1 0.5 1.59

Sri Lanka 2,767 871 869 1 0.5 3.18

Iran 2,348 587 16,837 0 0.4 4.00

Madagascar 2,300 1,207 2,565 1 0.4 1.91

Lao PDR 2,155 690 800 0 0.4 3.12

Colombia 2,100 440 2,079 0 0.4 4.77

Malaysia 2,037 692 1,820 0 0.3 2.94

Korea, DPR 1,690 535 1,700 0 0.3 3.16

Peru 1,665 300 3,670 0 0.3 5.55

Argentina b 1,658 289 25,000 0 0.3 5.74

Ecuador 1,520 380 1,574 0 0.3 4.00

Australia 1,400 145 53,775 0 0.2 9.66

Italy 1,300 221 8,280 0 0.2 5.89

Uruguay 1,175 185 1,260 0 0.2 6.35

Côte d’Ivoire 1,162 750 2,950 0 0.2 1.55

World 598,852 153,766 1,380,239 100 100.0 3.89


Arable land refers to land under temporar y crops (double-cropped areas are counted only once), temporar y meadows for mowing or pasture, land under

market and kitchen gardens, and land temporarily fallow or lying idle. The figures are for 1998. b Data for rice area and production are for 1999. Source of

basic data: FAO database, 2001.

one-fifth or more of planted area in the

ecologically more diverse countries of China

and India. Of 25 major rice-producing nations,

17 are located within this region (Table 2). The

eight countries outside the region jointly

produce less than 6% of the world’s rice.

In the years since World War II, world rice

area, yield, and production have changed considerably

(Table 3). From 1948 to 1990, the area

planted to rice increased by almost 71%, the

mean yield obtained from that area went up by

110%, and total production more than tripled.

During those four decades, rice became ever

more important as a human food. World rice

demand is predicted to increase at about 1% per

year from 2001 to 2025, roughly equal to

population growth in Asia during that period.

With the accelerating loss of productive

rice land to rising sea levels, salinization,

erosion, and human settlements, the problem

becomes one of increasing yields under ever

more trying circumstances. From 1965-67

through 1989-91, the improvements in productivity

spawned by the Green Revolution spread

rapidly. During those years, total rice production

almost doubled. Most of this increase came

from increased yields and increased cropping

intensity, although some resulted from new land

brought under cultivation or shifted into rice

from other crops. Much of the yield increase

could be traced to the introduction of the

dwarfing gene and to the increased use of fertilizer,

irrigation water, and other inputs. Further

yield increases have been constrained by

Importance of rice 5

Table 3. World rice area, yield, and production, various years.

Arable land +

Rough rice

Year permanent Area Yield Production

crops a (000 ha) (000 ha) (t/ha) (000 t)

1948 1,232,000 86,700 1.68 145,400

1953 1,332,000 109,025 1.82 197,906

1958 1,390,000 117,017 1.92 224,093

1963 1,355,864 120,277 2.05 247,139

1968 1,377,311 129,449 2.23 288,714

1973 1,397,696 136,824 2.45 334,988

1978 1,423,870 143,638 2.68 385,106

1983 1,454,147 143,074 3.14 449,048

1988 1,497,719 146,252 3.34 488,292

1993 1,504,732 145,811 3.63 529,803

1998 1,380,239 152,002 3.81 578,786

1999 1,511,766 156,462 3.88 607,780

2000 1,511,766 153,766 3.89 598,852


This column reports land in both temporary and permanent crops. Source of basic data: FAO production

yearbook, 1952; FAOSTAT database.

diminishing returns and have been increasingly

difficult to achieve.

Rice as human food

Rice, wheat, and maize are the three leading food

crops in the world; together they directly supply

more than 50% of all calories consumed by the

entire human population. Wheat is the leader in

area harvested each year with 214 million ha,

followed by rice with 154 million ha and maize

with 140 million ha (Table 4). Human consumption

accounts for 85% of total production for

rice, compared with 72% for wheat and 19% for


Rice provides 21% of global human per

capita energy and 15% of per capita protein.

Although rice protein ranks high in nutritional

quality among cereals, protein content is modest.

Unmilled (brown) rice of 17,587 cultivars in the

IRRI germplasm collection averages 9.5%

protein content, ranging from 4.3% to 18.2%.

Environmental factors (soil fertility, wet or

dry season, solar radiation, and temperature during

grain development) and crop management

(added N fertilizer, plant spacing) affect rice protein

content. Breeding efforts to increase protein

have been largely unsuccessful because of the

considerable effects of environment and because

of complex inheritance properties in the triploid

endosperm tissue.

Rice also provides minerals, vitamins, and

fiber, although all constituents except carbohydrates

are reduced by milling. Milling removes

roughly 80% of the thiamine from brown rice. A

precook rinse or a boiling of milled rice results

in additional loss of vitamins, especially B 1


Average calorie intake per person in some

developing countries—Cambodia and

Madagascar—is as low as 2,000/day, while in

some developed countries such as the U.S., it

reaches almost twice that amount. The proportion

that calories from rice make of the total

calorie intake also varies greatly, from threequarters

in developing countries such as

Bangladesh and Cambodia to only 2% in Turkey,

Mexico, and the former USSR countries. The

world average total calorie intake in 1999 was

2,808/person/day, of which rice made up 21%.

The world average consumption of rice in 1999

was 58 kg, with the highest intake in some Asian

countries; Myanmar has the highest annual

consumption at 211 kg/person (Table 5).

Rice eaters and growers constitute the bulk

of the world’s poor: according to the UNDP

Human Development Report for 1997,

approximately 70% of the world’s 1.3 billion

poor people live in Asia, where rice is the staple

food. To some extent, this reflects Asia’s large

population, but even in relative terms

malnutrition appears to affect a substantially

larger share of the population in South Asia than

in Africa. For these people, rice is the most

important commodity in their daily lives. In

countries such as Bangladesh, Vietnam, and

Myanmar, the average citizen consumes 150–200

kg annually, which accounts for two-thirds or

more of caloric intake and approximately 60% of

6 Rice almanac

Table 4. World food picture.

Human population (million) 6,055.1

Land use, 1998 (million ha)

Total land area 13,048.4

Arable land 1,380.2

Permanent crops 131.5

Permanent pastures 3,426.5

Forest and woodlands (1994) 4,157.2

Other land 3,952.9

Food production

Area Production Food (million t) Per capita/day (1999)

Crop (million ha) (million t) 1999 Calories Protein (g)

Rice (rough) 153.8 598.9 515.9 65% milling rate 577 11

Maize 139.7 590.8 113.0 80% for feed 156 4

Wheat 213.6 576.3 416.0 70% milling rate 537 16

Millet and sorghum 78.0 85.8 44.9 30% milling rate 62 2

Barley and rye, excluding beer 66.9 152.0 14.2 70% milling rate 17 0.4

Oats 12.8 26.0 2.9 65% milling rate 3 0.1

Potato 18.8 311.3 184.7 60% for feed 57 1

Sweet potatoes and yams 13.4 178.7 87.2 50% for feed 39 0.4

Subtotal 1,448 34.9

All foods 2,808 75

Table 5. Rice consumption, caloric intake, and percent of calories from rice,


Total b

Country Milled rice calories/ Rice calories/ %

consumption a capita/ capita/ calories

(kg/capita/year) day day from rice

Myanmar 211 2,803 2,050 73

Lao PDR 171 2,152 1,516 70

Vietnam 170 2,564 1,676 65

Bangladesh 168 2,201 1,676 76

Cambodia 165 2,000 1,527 76

Indonesia 154 2,931 1,525 52

Thailand 101 2,411 1,004 42

Philippines 100 2,357 974 41

Madagascar 91 1,994 926 46

China 91 3,045 911 30

India 74 2,417 736 30

Japan 60 2,782 642 23

Egypt 41 3,323 426 13

Brazil 40 3,012 409 14

Nigeria 23 2,833 237 8

Pakistan 15 2,462 150 6

South Africa 12 2,805 119 4

USA 9 3,754 94 3

Turkey 7 3,469 65 2

Mexico 6 3,168 61 2

USSR (former area) 5 2,778 47 2

World 58 2,808 577 21


Amount available for human consumption. b Data include all food available for human consumption. Source:

FAO online database (FAO update 31 May 2001).

daily protein consumption. Even in relatively

wealthier countries such as Thailand and

Indonesia, rice still accounts for nearly 50% of

calories and one-third or more of protein.

Rice is also the most important crop to

millions of small farmers who grow it on

millions of hectares throughout the region, and to

the many landless workers who derive income

Importance of rice 7

from working on these farms. In the future, it is

imperative that rice production continue to grow

at least as rapidly as the population, if not faster.

Rice research that develops new technologies for

all farmers has a key role to play in meeting this

need and contributing to global efforts directed at

poverty alleviation.

Where rice is the main item of the diet, it is

frequently the basic ingredient of every meal and

is normally prepared by boiling or steaming. In

Asia, bean curd, fish, vegetables, meat, and

spices are added depending on local availability

and economic situation. A small proportion of

rice is consumed in the form of noodles, which

serve as a bed for various, often highly spiced,

specialties or as the bulk ingredient in soups.

Most rice is consumed in its polished state.

When such rice constitutes a high proportion of

food, dietary deficiencies may result. Despite the

dramatic losses in food value resulting from

milling, brown rice is unpopular because (1) it

requires more fuel for cooking, (2) it may cause

digestive disturbances, and (3) oil in the bran

layer tends to turn rancid during storage even at

moderate temperatures.

In contrast, parboiling rough rice before milling,

as is common in India and Bangladesh, allows

a portion of the vitamins and minerals in the bran to

permeate the endosperm and be retained in the

polished rice. This treatment also lowers protein loss

during milling and increases whole-grain recovery.

Even though rice diets are often marginally

deficient in protein, vitamins, and minerals,

clinical manifestations of deficiency are not

common among people whose diets are

otherwise adequate in calories. The exception is

when people do heavy labor and their higher

calorie demand is met by an increase in rice

without a corresponding increase in other foods

such as legumes or fish. Under these conditions,

there is danger of beriberi, which is related to a

deficiency of thiamine or vitamin B 1


Research is under way to fortify rice with

micronutrients in areas where these are

inadequate in the diet. Vitamin A is an important

one—a severe lack causes irreversible blindness—and

has now been incorporated in a

variety known as Golden Rice. Another new

variety is rich in iron and zinc, micronutrients

often deficient in people consuming mainly rice.

These fortified rice varieties are being tested in

nutrition trials before they are grown


Rice and population

Agricultural population densities on Asia’s riceproducing

lands are among the highest in the

world and continue to increase at a remarkable

rate. Rapid population growth puts increasing

pressure on the already strained food-producing


The aggregate population of the less developed

countries grew from 2.3 billion in 1965 to

4.4 billion in 1995. Asia accounted for 60% of

the global population, about 92% of the world’s

rice production, and 90% of global rice

consumption. Even with rice providing 35–80%

of the total calories consumed in Asia and with a

slowing of growth in total rice area, rice

production more than kept up with demand in

2000. The largest producing countries—China,

India, Indonesia, Bangladesh, Vietnam, and

Thailand—together account for more than threequarters

of world rice production.

The world’s annual rough rice production,

however, will have to increase markedly over the

next 30 years to keep up with population growth

and income-induced demand for food. Although

the global population expanded by only 40

million in 1950, about 80 million people are

being added per year at the start of the 21st century

(Table 6), most in the less developed

countries where population growth is much

faster than in industrialized countries.

From 1961 to the early 1990s, the

proportion of rice traded on world markets

ranged from 3.5% to 5% of total production.

Since then, it has been gradually increasing to an

average of 6%. However, most countries rely

almost entirely on domestic production to feed

their populations. With less reliable supplies in

the past, the world rice trade was volatile, but

now is no more unstable than that for wheat or

maize. Nevertheless, rice is still regarded as a

political commodity in some Asian countries.

Specialty uses of rice

Glutinous rice plays an important role in some

cultures. In Lao PDR and northeast Thailand, for

example, glutinous rice is the staple food. In

other cultures, it is prepared in a sweetened form

for snacks, desserts, or special foods for religious

or ceremonial occasions. In a few areas, glutinous

rice is pounded and roasted to be eaten as a

breakfast cereal.

8 Rice almanac

Table 6. World population, 1995-2000, with projection

to 2050.

Year Population Annual growth Annual increase

(millions) rate (%) (millions)

1950 2,522 1.6 40

1960 3,022 1.8 55

1970 3,696 2.0 75

1980 4,440 1.9 82

1990 5,266 1.7 91

1995 5,666 1.5 84

2000 6,055 1.3 81

2010 6,795 1.2 79

2020 7,502 1.0 75

2025 7,824 0.8 66

2030 8,112 0.7 59

2040 8,577 0.6 48

2050 8,909 0.4 34

FAO Database, 2001.

Alcoholic beverages made from rice are

found throughout the rice-producing world. The

most common is a rice beer produced by boiling

husked rice, inoculating the mix with a bit of

yeast cake, and allowing the mixture to ferment

for a short period.

The mash left at the bottom of the container

is often prized. Among the Ifugao of the

Philippines, the mash is frequently reserved for

the village priest. Among the Kachins of

Myanmar, it is the first food offered to a recently

captured and hungry wild elephant. Kachins believe

that the elephant will be loyal forever to the

person who first provides such a meal.

Sake is widely consumed in Japan, as is

wang-tsiu in China. These rice-based winelike

beverages are served warm and featured at

ceremonial feasts.

In some parts of the world, especially in

North America and Europe, rice is developing a

new market niche as a staple and as a gourmet

food. This trend appears to be related to the

arrival of large numbers of immigrants from

Southeast Asia, who introduced aromatic rice to

markets where it was previously unknown. It has

been adopted by a food quality-conscious public

over the past several years.

In much of Tanzania, rice is used for making

bread; in the south, it is also used in ceremonies.

In West Africa, rice bread, rice cake, and rice

porridge are used for ceremonies such as funerals

and weddings. Some “old” varieties (most likely

O. glaberrima) are used in traditional religious

rituals in West Africa, while certain parts of

some varieties are used as medicines in the

traditional treatment of illnesses.

An extensive list of other ways of using rice

is given by FAO 1 :

• Milled rice is marketed precooked,

canned, dried, and puffed for breakfast

cereals as rice flour; extrusion-cooked

foods; puddings and breads; cakes and

crackers; noodles and rice paper; fermented

foods and vinegars; rice starch;

and syrups.

Rice bran, which forms 5% to 8% of the

grain weight, is used as livestock feed, a

pickling medium, a medium for growing

mushrooms, and as a growing medium

for some enzymes, as well as for flours,

concentrates, oils, and dietary fiber.

• Hulls and husks, about 20% of the grain

weight, are used for fuel, bedding, and

incubation material, and as a seedbed medium,

as well as being sometimes incorporated

in livestock feeds, concrete

blocks, tiles, fiberboard, ceramics,

cement, filters, charcoal briquettes, and

cooking gas production.

Rice straw, more or less equivalent in

production weight to grain, is used as fuel

for cooking, roofing material, livestock

feed, fertilizer, and a medium for growing



FAO Rice Information Vol. 2, January 2000. FAO, Rome.

Importance of rice 9

The rice plant and its ecology


Cultivated rice is generally considered a

semiaquatic annual grass, although in the

tropics it can survive as a perennial,

producing new tillers from nodes after harvest

(ratooning). At maturity, the rice plant has a main

stem and several tillers. Each productive tiller

bears a terminal flowering head or panicle. Plant

height varies by variety and environmental conditions,

ranging from approximately 0.4 m to

more than 5 m in some floating rice. The

morphology of rice is divided into the vegetative

phase (including germination, seedling, and

tillering stages) and the reproductive phase (including

panicle initiation and heading stages).






Aleurone layer









Brown rice



The rice grain, commonly called a seed, consists

of the true fruit or brown rice (caryopsis) and the

hull, which encloses the brown rice. Brown rice

consists mainly of the embryo and endosperm.

The surface contains several thin layers of differentiated

tissues that enclose the embryo and

endosperm (Fig. 1).

The palea, lemmas, and rachilla constitute

the hull of indica rice. In japonica rice, however,

the hull usually includes rudimentary glumes and

perhaps a portion of the pedicel.

A single grain weighs about 10–45 mg at 0%

moisture content. Grain length, width, and thickness

vary widely among varieties. Hull weight

averages about 20% of total grain weight.


Germination and seedling development start

when seed dormancy has been broken and the

seed absorbs adequate water and is exposed to a

temperature ranging from about 10 to 40 °C. The

physiological definition of germination is usually

the time when the radicle or coleoptile

(embryonic shoot) emerges from the ruptured

seed coat. Under aerated conditions, the seminal

root is the first to emerge through the coleorhiza



Fig. 1. Cross-section of the rice grain.

from the embryo, and this is followed by the

coleoptile. Under anaerobic conditions, however,

the coleoptile is the first to emerge, with the

roots developing when the coleoptile has reached

the aerated regions of the environment.

If the seed develops in the dark as when

seeds are sown beneath the soil surface, a short

stem (mesocotyl) develops, which lifts the crown

of the plant to just below the soil surface (Fig. 2).

After the coleoptile emerges, it splits and the

primary leaf develops.

Tillering plants

Each stem of rice is made up of a series of nodes

and internodes (Fig. 3). The internodes vary in

length depending on variety and environmental

conditions, but generally increase from the lower

to the upper part of the stem. Each upper node

bears a leaf and a bud, which can grow into a

tiller. The number of nodes varies from 13 to 16,

with only the upper 4 or 5 separated by long

The rice plant and its ecology 11


Nodal roots

(or adventitious)



Seminal root


Second leaf

(first complete leaf)

Primary leaf

(first complete leaf)


Fig. 2. Parts of a young seedling germinated in the


Leaf sheath




Nodal roots

Mat roots

Ordinary roots

Fig. 3. Parts of the rice stem and tillers.

Leaf blade



Leaf sheath

Crown roots

internodes. Under rapid increases in water level,

some deepwater rice varieties can also increase

the lower internode lengths by more than 30 cm


The leaf blade is attached at the node by the

leaf sheath, which encircles the stem. Where the

leaf blade and the leaf sheath meet is a pair of

clawlike appendages, called the auricles. Coarse

hairs cover the surface of the auricles. Immediately

above the auricles is a thin, upright

membrane called the ligule.

The tillering stage starts as soon as the seedling

is self-supporting and generally finishes at

panicle initiation. Tillering usually begins with

the emergence of the first tiller when seedlings

have five leaves. This first tiller develops

between the main stem and the second leaf from

the base of the plant. Subsequently, when the

sixth leaf emerges, the second tiller develops

between the main stem and the third leaf from

the base.

Tillers growing from the main stem are

called primary tillers. These may generate

secondary tillers, which may in turn generate

tertiary tillers. These are produced in a synchronous

manner. Although the tillers remain attached

to the plant, at later stages they are

independent because they produce their own

roots. Varieties and races of rice differ in tillering

ability. Numerous environmental factors also

affect tillering such as spacing, light, nutrient

supply, and cultural practices.

The rice root system consists of two major

types: crown roots (including mat roots) and nodal

roots (Fig. 3). In fact, both these roots develop

from nodes, but crown roots develop from nodes

below the soil surface. Roots that develop from

nodes above the soil surface usually are referred

to as nodal roots. Nodal roots are often found in

rice cultivars growing at water depths above 80

cm. Most rice varieties reach a maximum depth

of 1 m or more in soft upland soils. In flooded

soils, however, rice roots seldom exceed a depth

of 40 cm. That is largely a consequence of limited

O 2

diffusion through the gas spaces of roots

(aerenchyma) to supply the growing root tips.

Panicle and spikelets

The major structures of the panicle are the base,

axis, primary and secondary branches, pedicel,

rudimentary glumes, and spikelets. The panicle

axis extends from the panicle base to the apex; it

has 8–10 nodes at 2- to 4-cm intervals, from

which primary branches develop. Secondary

branches develop from the primary branches.

Pedicels develop from the nodes of the primary

12 Rice almanac

Flag leaf







Primary branch



Paleal apiculus









Sterile lemmas

Rudimentary glumes


Fig. 4. Rice panicle and spikelets.

and secondary branches; the spikelets are

positioned above them (Fig. 4).

Since rice has only one fully developed

floret (flower) per spikelet, these terms are often

used interchangeably. The flower is enclosed in

the lemma and palea, which may be either awned

or awnless. The flower consists of the pistil and

stamens, and the components of the pistil are the

stigmas, styles, and ovary.


The growth duration of the rice plant is 3–6

months, depending on the variety and the

environment under which it is grown. During

this time, rice completes two distinct growth

phases: vegetative and reproductive. The vegetative

phase is subdivided into germination, early

seedling growth, and tillering; the reproductive

phase is subdivided into the time before and after

heading, that is, panicle exsertion. The time after

heading is better known as the ripening period

(Fig. 5).

Potential grain yield is primarily determined

before heading. Ultimate yield, which is based

on the amount of starch that fills the spikelets, is

largely determined after heading. Hence,

agronomically, it is convenient to regard the life

history of rice in terms of three growth phases:

vegetative, reproductive, and ripening. A 120-d

variety, when planted in a tropical environment,

spends about 60 d in the vegetative phase, 30 d

in the reproductive phase, and 30 d in the

ripening phase.

Vegetative phase

The vegetative phase is characterized by active

tillering, a gradual increase in plant height, and

The rice plant and its ecology 13

Amount of growth



Tiller number

Grain weight

Plant height



0 30 60 90 120

Days after germination



Seedling growth

Active tillering

End of effective tillering

Maximum tiller number

Panicle primordia initiation







Vegetative Reproductive Ripening

Fig. 5. Schematic of growth of a 120-d rice variety

in the tropics.

leaf emergence at regular intervals. Tillers that

do not bear panicles are called ineffective tillers.

The number of ineffective tillers is a closely

examined trait in plant breeding since it is

undesirable in irrigated varieties, but sometimes

an advantage in rainfed lowland varieties in

which productive tillers or panicles may be lost

because of unfavorable conditions.

Reproductive phase

The reproductive growth phase is characterized

by culm elongation (which increases plant

height), a decline in tiller number, emergence of

the flag leaf (the last leaf), booting, heading, and

flowering of the spikelets. Panicle initiation is

the stage about 25 d before heading when the

panicle has grown to about 1 mm long and can

be recognized visually or under magnification

following stem dissection.

Spikelet anthesis (or flowering) begins with

panicle exsertion (heading) or on the following

day. Consequently, heading is considered a synonym

for anthesis in rice. It takes 10–14 d for a

rice crop to complete heading because there is

variation in panicle exsertion among tillers of the

same plant and among plants in the same field.

Agronomically, heading is usually defined as the

time when 50% of the panicles have exserted.

Anthesis normally occurs from 1000 to 1300

hours in tropical environments and fertilization is

completed within 6 h. Very few spikelets have

anthesis in the afternoon, usually when the

temperature is low. Within the same plant, it

takes 7–10 d for all the panicles to complete

anthesis; the spikelets themselves complete

anthesis within 5 d.

Ripening follows fertilization and can be

subdivided into milky, dough, yellow-ripe, and

maturity stages. These terms are primarily based

on the texture and color of the growing grains.

The length of ripening varies among varieties

from about 15 to 40 d. Ripening is also affected

by temperature, with a range from about 30 d in

the tropics to 65 d in cool temperate regions,

such as Hokkaido, Japan, and Yanco, Australia.


Rice soils are wetland soils that are grown to

rice. Wetlands are defined as having free water at

or near the surface for at least the major part of

the growing season of arable crops, or for at least

2 mo of the growing season of perennial crops,

grasslands, forests, or other vegetation. The

floodwater is sufficiently shallow to allow the

growth of a crop or of natural vegetation rooted

in the soil. Free surface water may occur

naturally, or rainfall, runoff, or irrigation water

may be retained by field bunds, puddled plow

layers, or traffic pans.

Wetlands have at least one wet growing

season, but may be dry, moist, or without surface

water in other seasons. Wetland soils may

therefore alternately support wetland and upland

crops when cultivated.

The transition from wetlands to uplands is

often gradual. It may fluctuate from year to year,

depending on variations in precipitation, runoff,

or irrigation. If water (both drainage and irrigation)

can be fully controlled, farmers can choose

to establish wetlands or uplands. But, in most

wetlands, drainage capacities are insufficient to

prevent soil submergence during the rainy season,

particularly in the lowlands of the humid tropics.

The presence of “aquic” soil conditions is

indicated by redoximorphic features, such as

zones of accumulation and depletion of Fe and

14 Rice almanac

Table 1. Typical profile of a flooded rice soil.








A layer of standing water that becomes

the habitat of bacteria,

phytoplankton, macrophytes (submerged

and floating weeds),

zooplankton, and aquatic invertebrates

and vertebrates. The chemical status

of the floodwater depends on the

water source, soil, nature and biomass

of aquatic fauna and flora, cultural

practices, and rice growth. The pH of

the standing water is determined by

the alkalinity of the water source, soil

pH, algal activity, and fertilization.

Because of the growth of algae and

aquatic weeds, the pH and O 2


undergo marked diurnal fluctuations.

During daytime, the pH may increase

to 11 and the standing water becomes

oversaturated with O 2

because of photosynthesis

of the aquatic biomass.

Standing water stabilizes the soil

water regime, moderates the soil temperature

regime, prevents soil erosion,

and enhances C and N supply.

The floodwater-soil interface that

receives sufficient O 2

from the floodwater

to maintain a pE + pH value


above the range below which NH 4


the most stable form of N. The

thickness of the layer may range from

several millimeters to several

centimeters, depending on

pedoturbation by soil fauna and the

percolation rate of water.

The reduced puddled layer is characterized

by the absence of free O 2


the soil solution and a pE + pH value

below the range at which Fe(III) is


A layer that has increased bulk density,

high mechanical strength, and

low permeability. It is frequently

referred to as a plow or traffic pan.

The characteristics of the B horizon

depend highly on water regime. In

epiaquic moisture regimes, the horizon

generally remains oxidized, and

mottling occurs along cracks and in

wide pores. In aquic moisture regimes,

the whole horizon, or at least

the interior of soil peds, remains

reduced during most years.

Mn. Plowing and puddling often result in the

development of a dense layer below the cultivated


Three types of water saturation occur in rice

soils: (1) endosaturation, in which the entire soil

is saturated with water; (2) episaturation, in

which upper soil layers are saturated but underlain

by unsaturated subsoil layers; and (3) anthric

saturation, a variant of episaturation with

controlled flooding and puddled surface soil.

The properties of a typical soil profile of a

flooded rice soil during the middle of a growing

season are shown in Table 1.

Many rice-growing countries have developed

classification systems that distinguish

natural wetland soils from rice soils. The only

soil classification systems applicable worldwide

are found in the legend of the FAO-UNESCO

Soil Map of the World and the U.S. Department

of Agriculture Soil Taxonomy.

In the FAO-UNESCO Soil Map of the

World, Gleysols, Fluvisols, Planosols, Plinthosols,

and Histosols make up most of the wetland

soils. Gleyic subunits of Arenosols, Andosols,

Cambisols, Solonetz, Solonchaks, Chernozems,

Pharozems, Greyzems, Luvisols, Podsoluvisols,

Podsols, Lixisols, Acrisols, and Alisols are also

mostly wetland soils. Although Vertisols, Nitosols,

and Ferralsols have no gleyic subunits,

these soils may be artificially flooded and sown

to rice.

Soil taxonomy does not recognize wetland

soils, but classifies soils with aquic conditions at

the suborder level and soils with hydromorphism

at the subgroup level. Most hydromorphic soils,

which have an aquic moisture regime, are

equivalent to wetland soils in soil taxonomy.

Suborders with aquic conditions are found in the

orders of Spodosols, Andosols, Oxisols,

Vertisols, Ultisols, Mollisols, Alfisols,

Inceptisols, and Entisols. Most Histosols are

wetland soils per se. Practically all Aridisols are

upland soils. Soils within the aquic subgroups

showing hydromorphism generally are not

wetland soils because signs of wetness are found

only in subsoil horizons.

Research is now being conducted to grow

rice on dry, but irrigated land. See “aerobic rice”

on page 32.

The rice plant and its ecology 15


The rice plant’s environments have been divided

into agroecological zones (AEZs), which are

geographic mapping units developed by FAO.

They are based on climatic conditions and land

forms that determine relatively homogeneous crop

growing environments. Characterization of AEZs

permits a quantitative assessment of the biophysical

resources upon which agriculture and forestry

research depend.

The classification system distinguishes

among tropical regions, subtropical regions with

summer or winter rainfall, and temperate regions.

These major regions are further subdivided into

rainfed moisture zones, lengths of growing period,

and thermal zones based on the temperature regime

that prevails during the growing season.

The definitions of terms used in AEZ classifications



regions with monthly mean temperature,

corrected to sea level, of >18 °C

for all months

subtropics regions with monthly mean temperature,

corrected to sea level, of


































Dominant agroecological zones


1 Warm arid and semiarid tropics

2 Warm subhumid tropics


3 Warm humid tropics

5 Warm arid and semiarid subtropics

with summer rainfall

6 Warm subhumid subtropics with summer rainfall

7 Warm/cool humid subtropics with summer rainfall

8 Cool subtropics with summer rainfall

Fig. 6. Regional agroecological zones in Asia.






Table 2. Asian rice areas as of mid-1990s (000 ha).

Deepwater Irrigated Rainfed

State Upland (flood-prone) Total rice

(>100 cm) Wet Dry Shallow Intermediate area

(0–30 cm) (30–100 cm)

India 5,060 1,364 15,537 4,123 11,985 4,447 42,516

China 499 0 20,490 9,146 1,990 0 32,125

Indonesia 1,209 2 2,963 2,963 2,872 1,006 11,015

Bangladesh 697 1,220 351 2,267 3,271 2,873 10,679

Thailand 203 342 274 665 6,382 1,778 9,644

Vietnam 322 177 1,630 1,630 1,963 651 6,373

Myanmar 214 362 1,812 1,386 2,033 478 6,285

Philippines 165 0 1,175 1,029 911 341 3,621

Pakistan 0 0 2,125 0 0 0 2,125

Cambodia 24 152 140 165 1,069 349 1,899

Nepal 68 118 706 24 406 166 1,488

Korea, Rep. of 1 0 776 0 326 0 1,103

Sri Lanka 0 0 377 251 213 26 867

Korea, DPR 88 0 456 0 136 0 680

Malaysia 80 0 228 210 135 15 668

Lao PDR 219 0 33 11 348 0 611

Taiwan, China 0 0 133 133 0 0 266

Bhutan 4 0 5 0 16 1 26

Total 8,853 3,737 49,211 24,003 34,056 12,131 131,991

Source: Huke RE, Huke EH. 1997. Rice area by type of culture: South, Southeast, and East Asia. IRRI, Los Baños, Philippines.

The rice plant and its ecology 17

egions where modern rice technologies have yet

to make an impressive impact; area expansion

has been an important source of growth in rice

production. Strategic research is needed for

these regions, not only for maintaining the

natural resource base but also for genetic

improvements of germplasm, so that constraints

to increased rice production imposed by abiotic

and biotic stresses—droughts, floods,

waterlogging, salinity, weeds, pests, and

diseases—can be minimized.

Irrigated rice ecosystem

Physical description

Irrigated rice is grown in bunded fields with

assured irrigation for one or more crops a year.

Rainfall variability is the basis for subdividing

the irrigated ecosystem into irrigated wet season

and irrigated dry season.

Irrigated wet season areas are those where

irrigation water may be added to the rice fields

during the wet season as a supplement to rainfall.

Relatively small volumes of water early in the

season or during a midseason dry period can pay

large dividends in assuring the success of a crop

threatened by erratic precipitation.

Irrigated dry season areas are those where

no rice crop can be grown without supplemental

water during the rice season. Rainfall is usually

very low, cloud cover is minimal, and the levels

of incoming solar radiation are markedly above

those of the rainy season. In the dry season,

evapotranspiration is high and water needs are

considerably greater than during the wet season.

In most areas, the combination of assured water

throughout the season, high solar radiation, low

pest incidence, and high input levels results in

high yields.

Worldwide, about 79 million ha of rice are

grown under irrigated conditions. Average yields

vary from 3 to 9 t/ha. Because the risk of crop

failure is lower than in the other ecosystems,

farmers of irrigated land use more purchased

inputs than in nonirrigated production. Even

though irrigated rice represents only about onehalf

of the world’s rice land, more than 75% of

the world’s rice supply is produced from

irrigated rice. Improved rice cultivars that have

been developed for irrigated rice are short in

height and responsive to N fertilization. Equally

important is their short duration, allowing two

and sometimes three crops per year. Additionally,

most improved cultivars have resistance to

several insects and diseases and some tolerance

for adverse soils.

East Asia, 93% of which is irrigated,

accounts for about 43% of the world’s irrigated

rice area. In the tropics of South and Southeast

Asia, only about 40% of the rice area is irrigated.

In West Africa, only about 10.5% of the rice area

is irrigated.


Based on current national or regional yield

averages, the irrigated rice ecosystem can be

divided into high-yielding areas where yields are

>5 t/ha, medium-yielding areas with yields of 4–

5 t/ha, and low-yielding areas that typically

achieve yields of

growth duration (around 100 d), greater yield

stability due to genetic resistance to pests, and, to

a lesser extent, tolerance for some environmental

stresses such as problem soils.

Breeding programs have improved grain

quality and increased grain size and milling

recovery of the modern, high-yielding varieties.

Increasing nutritional value by incorporating

micronutrients such as iron and zinc or betacarotene

(vitamin A) are currently goals of the

breeding program at IRRI.

The irrigated ecosystem benefited greatly

from the development of associated management

practices that allow the semidwarf varieties to

express their yield potential. In partnership with

national agricultural research and extension

systems, international research on the irrigated

rice ecosystem focuses on yield-limiting factors

and technological advances to overcome them.

Research is also conducted on the resilience of

intensively cropped systems, including

identifying factors that contribute to stagnating

or even declining yields.

The objectives of IRRI’s research are to

extend the yield frontier through varietal

improvement, more efficient use of inputs, and

rehabilitation and maintenance of the physical,

biological, and natural resource base. Technologies

to increase the efficiency with which the

rice crop uses inputs should improve rice lands,

reduce dependence on pesticides, and increase

the profitability of rice production.

WARDA emphasizes integrated rice

management options and short-duration, highyielding

cultivars that are weed-competitive and

N-use efficient to close the yield gap, that is, the

difference between actual yields in farmers’

fields and yield potentials of existing rice


Rainfed lowland rice ecosystem

Physical description

Rainfed lowland rice grows in bunded fields that

are flooded for at least part of the cropping

season to water depths that exceed 100 cm for no

more than 10 consecutive days. Rainfed

lowlands are characterized by a lack of water

control, with floods and drought being potential

problems. In favorable rainfed lowlands, small

investments in water-control measures can

increase water control considerably. In these

cases, cropping systems are on a continuum

between rainfed and irrigated ecosystems and

available technologies of the irrigated sector

need only minor adaptations. Considerable

adaptations or different technologies are needed

in the rainfed lowlands where risk of drought or

flood is significant. About 34% of the world’s

total rice land or approximately 54 million ha are

rainfed. Adverse climate, poor soils, and a lack

of suitable modern technologies keep farmers

from being able to increase productivity.

The rainfed lowland rice ecosystem can be

divided into four subecosystems: (1) favorable

rainfed lowland, (2) drought-prone, (3)

submergence-prone, and 4) drought- and

submergence-prone. Technologies for the

irrigated rice sector can be applied in the rainfed

lowland ecosystem only where there is no

significant risk of drought or flood. However, the

majority of lands in this ecosystem do face these

risks, requiring different rice varieties and

management strategies from those used in the

irrigated ecosystem.

Another ecosystem that has significant

potential for rainfed rice production is inland

valleys, particularly in Sub-Saharan Africa. This

is discussed in “International rice research and

development” (pages 51-52).

Predominant cropping systems

The rainfed lowlands include areas in which

farmers grow only one crop of rice, although in

some areas farmers grow rice and a postrice

crop, usually on a smaller area. The main postrice

crops are chickpea, mustard, linseed, rice,

and mungbeans, followed to a lesser extent by

vegetables, maize, wheat, and other legumes

such as soybeans and lentils. The choice depends

on water availability and season duration.

Farmers often cultivate rainfed lowland rice at

several toposequence levels such that on one

farm some fields may be drought-prone, while

others may be flood- and submergence-prone in

the same season.


The world’s rainfed lowlands offer substantial

potential for increasing rice production.

Population pressure on arable land is low; the

area planted is increasing, but yields remain low.

Farmers have developed a range of practices that

address variability across sites as well as

heterogeneity within local ecosystems.

The rice plant and its ecology 19

Production constraints

Uncertainty characterizes rice farming in rainfed

lowlands. Crops suffer from droughts, floods,

pests, weeds, and soil constraints. Since most

rainfed lowlands depend on erratic rainfall,

conditions are diverse and unpredictable.

Understanding how farmers’ practices help

reduce risk and assure some production is

essential to developing improved technologies

for the rainfed lowlands.

Most rainfed lowland rice farmers are poor

and must cope with unstable yields and financial

risks. They adapt their cropping practices to the

complex risks, potentials, and problems they face.

They typically grow traditional, photoperiodsensitive

cultivars and invest their labor instead of

purchasing inputs. Farmers bund the fields to store

water. They weed, may redistribute seedlings to

ensure good crop stands, and usually harvest by

hand. Suitable modern varieties and associated

production technologies have been limited.

Although new technology developed in the

1960s and 1970s focused on the irrigated sector,

rainfed lowland rice farmers were not forgotten.

Researchers have tried to produce new varieties

and improved farming practices for nutrient

management, crop establishment, on-farm water

collection, and weed and pest control. These

practices can potentially contribute to higher

yields, especially in the favorable rainfed


Rainfed lowland rice farmers in less

favorable areas use traditional varieties that do

not respond well to higher fertilizer rates. In

Bangladesh, eastern India, Indonesia,

Philippines, and Thailand, however, adoption of

new rice varieties is increasing as scientists are

now developing new breeding lines with single

or combined traits adapted to rainfed lowland

stresses. Rice varieties that are bred for tolerance

for submergence, late transplanting, and

resistance to lodging allow farmers to apply

fertilizers and use more intensive weed

management practices. Decentralized regional

breeding programs developed in northeastern

Thailand and eastern India, focusing on droughtand

submergence-tolerant improved lines,

respectively, now have advanced lines under

evaluation in farmers’ fields.

Rainfed lowland rice varieties of the future

will need to respond to improved management

while retaining the tolerance of the traditional

varieties for drought, floods, and soil stresses.

Such varieties should perform well under

favorable conditions and still equal the

productivity of traditional cultivars under

adverse conditions. Farmers would then be able

to invest money and labor in potentially more

productive land preparation and fertility

management practices that will assure higher


Upland rice ecosystem

Physical description

Upland rice is grown in Asia, Africa, and Latin

America. Of about 150 million ha of world rice

area in the mid-1990s, about 14 million ha were

planted to upland rice: 8.9 million ha in Asia, 3.1

million ha in Latin America, and 1.8 million ha

in Africa. Although upland rice constitutes a

relatively small proportion of the total rice area,

it is the dominant rice culture in Latin America

and West Africa. In Asia, the area of the upland

ecosystem is much larger than the area under

rice, because rice is grown in rotation with many

other crops.

Upland rice is grown in low-lying valley

bottoms to undulating and steep sloping lands

with high runoff and lateral water movement. In

Southeast Asia, most upland rice is grown on

rolling and mountainous land with slopes

varying from 0% to more than 40%. In eastern

India, upland rice is grown on several million

hectares in permanently cultivated, level fields at

the top of a toposequence ranging from rainfed

lowland to upland. In West Africa, upland rice

grows on hills in the humid zone and on flatland

in the drought-prone and moist forest zones.

Most upland rice in Brazil is on level to gently

rolling (0–8% slope) land, much under

mechanized cultivation. In northern and

northeastern Brazil, some upland rice is grown

on rolling topography under shifting cultivation.

Upland rice soils range from erodible, badly

leached Alfisols in West Africa to fertile volcanic

soils in some areas in Southeast Asia. Their

texture, water-holding capacity (WHC), cation

exchange capacity (CEC), nutrient status, and

soil-related problems vary greatly. In Southeast

Asia, many upland soils in high-rainfall areas

where rice is grown are erodible, acidic, and

highly P-fixing. Subsoil acidity and Al toxicity

are common additional constraints, along with

severe nutrient deficiency and poor WHC. In

Brazil, where upland rice is a major crop, soils

have extremely low CEC values, high P fixation,

20 Rice almanac

and high levels of exchangeable Al. Upland rice

soils in most of Africa have low available WHC

because of coarse texture, are often kaolinitic

(i.e., low-activity clay soil with low CEC), and

have severe nutrient deficiencies and Al and Mn


Dry soil preparation and direct seeding in

fields that are generally unbunded are common

in upland rice culture. Surface water does not

accumulate for any significant time during the

growing season. In some countries such as in

eastern India and Bangladesh, upland rice fields

are frequently bunded to save scarce water.

Upland rice and food security

Upland rice is primarily grown as a subsistence

crop. It is critical to the food security of

impoverished communities that do not produce

enough lowland rice to meet their needs. In

eastern India and Bangladesh, upland rice is

grown by farmers who also have lowland fields,

but who face a “hungry month” before lowland

crops can be harvested; the upland crop, which is

harvested early, bridges the family through a

period when food is extremely scarce. In other

areas such as the mountains of northern Lao

PDR, many farm families have no lowland

holdings and are heavily dependent on upland

rice for subsistence. A commercial cropping

system with an upland rice component has

emerged only in the Brazilian Cerrado region

and in northern China (see below).

In Côte d’Ivoire, Guinea, Guinea Bissau,

and Sierra Leone, upland rice is the only staple

available between the maize and cassava

harvests, or between sweet potato and cassava.

Recently, interspecific hybrid rice (or NERICA)

has been the main food available in the “hunger

period” from late September to late November

(see page 36).

Predominant cropping systems

Depending on the size of their farms and their

resources, upland rice farmers use farming

systems ranging from shifting to permanent

cultivation. Shifting cultivation is common in

Indonesia, Lao PDR, northern Thailand, and

Vietnam in Asia, and in the forested areas of

Latin America and West Africa. Farmers plant a

rice crop alone or in association with other crops

such as maize, yam, beans, cassava, or plantains.

In many places, including Indonesia, the

Philippines, Southwest China, and Brazil, upland

rice may be intercropped with maize. In areas

with sufficient rainfall, upland rice may be

followed by a crop of maize, cowpea, beans,

soybean, or sweet potato. In West Africa, one or

more crops may be mixed with upland rice.

Farmers use an area for 1–3 yr until soil fertility

declines and weed and pest infestations increase.

They then abandon the land and return to

previously abandoned farmland or start cropping

on other available fallow land. In traditional

shifting cultivation systems, fallow periods were

as long as 30 years. This lengthy fallow restored

fertility and prevented weed seed buildup. Now,

rotations in most upland areas practicing shifting

cultivation have shortened to a 2- or 3-yr cycle

because of increased population pressure. This

has resulted in increased weed pressure and

reduced soil fertility.

One variation of shifting rice cultivation is

pioneer cultivation where fallow is replaced by

perennial vegetation such as pasture or trees.

Rice is intercropped with young fruit and forest

trees for 2–3 yr (intercalary cultivation). As the

trees grow, they shade more area and less rice is

planted. After a few years, the rice crop is

transferred to a new area. Pioneer cultivation is

common in Brazil, but rare in Asia and Africa,

although it is becoming popular in Indonesia

under rubber, oil palm, and teak.

Permanent cultivation of upland rice is

practiced in many Asian and Latin American

countries. This is characterized by orderly intercropping,

relay cropping, and sequential

cropping with several crops. The largest area of

permanent upland rice cultivation is in eastern

India. In the Chhattisgarh Plateau area of

Jharkand and Bihar, rainfall will support only a

single upland crop per season. Rice may be

grown continuously or rotated with legumes and

pasture. Rice yields in continuous production

tend to be very low (around 1 t/ha) because of

nematode buildup and other biotic factors that

are not well understood, but yields in rotation

with legumes may exceed 2 t/ha. In eastern Uttar

Pradesh, upland rice is usually double-cropped

with gram, mustard, or other upland crops.

Because the risk of crop damage or loss resulting

from drought or pests is high, and because

upland rice farmers are usually poor and have

limited access to credit, most apply few inputs of

animal manure, organic matter, chemical

fertilizer, and pesticide to upland rice crops. This

is particularly true in areas where farmers

The rice plant and its ecology 21

produce rice on both lowland and upland fields.

In such areas, farmers invest more in their

lowland fields, where greater response to inputs

is usually obtained.

Upland rice is grown in an intensively

managed commercial system in the Brazilian

Cerrado, where it is rotated with soybean and

pasture and often receives supplemental

irrigation. Rice is grown no more often than one

season in three because of the yield decline

associated with continuous or short-rotation

upland rice production. Commercial, high-input

upland rice production with supplemental

irrigation is also emerging in water-short areas of

northern China. These intensively managed

upland crops are now usually referred to as

“aerobic rice” to distinguish them from

traditional low-input rice crops. Areas planted to

aerobic rice in Asia can be expected to increase

because of water shortages in some areas

currently growing irrigated lowland rice.


Although accounting for 13% of total world rice

area, upland rice contributes only 4% to total

world rice production. Grain yields average

about 1 t/ha in traditional low-input systems, but

may reach about 2 t/ha in favorable upland

environments such as those found in Mindanao,

Philippines. In the Brazilian state of Mato

Grosso, where upland rice is grown with

supplemental irrigation and high inputs of N,

yields averaged nearly 2.5 t/ha in 1998-99.

Aerobic rice yields of more than 5 t/ha have been

reported in China and Brazil.

Production constraints

Biological and physical constraints to upland rice

yield are numerous. Weeds are the most severe

biological constraint, followed by blast disease

and brown spot. Weeds reduce upland rice grain

yield and quality. Estimates of yield losses

caused by weeds in upland rice range from 30%

to 100%. Small farmers using traditional

production systems cannot afford chemical weed

control, but herbicides are used in commercial

aerobic rice systems in Brazil and China. Stem

borers and rice bugs are the predominant insect

pests. Nematodes can cause yield losses of up to

30%. Rodents are reported in many countries as

a major problem and birds are sometimes serious


Amount and distribution of rainfall and poor

soil fertility are the most serious physical

constraints. In Asia, the monsoonal rainfall

ranges from 1,500 mm to more than 3,500 mm.

Rainfall is usually erratic during the monsoon

season. In Africa, annual rainfall ranges from

1,200 to 2,000 mm where upland rice is grown.

Rainfall is frequently erratic in semiarid areas of

West Africa. Mean annual rainfall in Latin

America ranges from 1,400 mm in central Brazil

to 4,800 mm in Costa Rica. Dry spells frequently

occur during the growing season in most of these

areas, mainly in northern and central Brazil.

Upland rice soils are predominantly acidic

(pH varies from 4 to 6) and depleted in major

elements. In South and Southeast Asia, more

than half of the upland rice is grown in infertile

soils. In most upland soils, P rather than N is the

most common limiting nutrient. Physiological

disorders result from major and trace element

imbalances. Major toxicities are caused by high

Al and Mn content in strongly acidic soils.

The temperature of most regions of Asia,

Latin America, and Africa is relatively favorable

to upland rice except in some high-altitude areas

in India, Indonesia, Myanmar, Nepal, and

Thailand. Minimum and maximum temperatures

average 20 and 30 °C for Latin America, 20 and

32 °C for South Asia, and 18 and 35 °C for

Africa. The optimum temperature for maximum

rice photosynthesis is 25–30 °C.

Flood-prone rice ecosystem

Physical description

The flood-prone ecosystem has several

environments and incorporates a number of rice

plant types. These rice plants must be adapted to

conditions such as (1) deepwater: submergence

in depths usually exceeding 100 cm and for

durations ranging from >10 d to 5 mo, requiring

the plant to elongate greatly to reach the surface;

floating rice up to 5 m long is included here; (2)

flash flood for periods of longer than 10 d; (3)

salinity caused by tides in extensive low-lying

coastal areas, where plants are subject to daily

tidal submergence; the plants do not elongate

greatly but tillering and tiller survival are at risk;

and (4) problem soils, such as acid-sulfate and

sodic soils, in which the problem is often excess

water, but not necessarily prolonged

submergence. Around 11 million ha of rice lands

worldwide are affected by one or more of these


22 Rice almanac

In these environments, rice yields are low

and extremely variable because of problem soils

and unpredictable combinations of drought and

flood. Although average yields are only about 1.5

t/ha, these areas support more than 100 million


Crucial for survival and production of the

rice crop are the age of plants at the start of

inundation, the rate of water rise, and the

duration of the flood. Many parts of the tidal,

deepwater, and rainfed lowland rice areas are

subject to sudden increases in water level, commonly

called flash floods. These floods occur

after heavy rain, local or remote, and may

completely submerge the crop for several days.

The water is often heavily laden with silt, which

covers the leaves of the plants.

Deepwater rice and floating rice are mainly

grown in fields on the floodplains and deltas of

rivers such as the Ganges and Brahmaputra of

India and Bangladesh, the Irrawaddy of

Myanmar, the Mekong of Vietnam and

Cambodia, the Chao Phraya of Thailand, and the

Niger of West Africa. Flooding occurs in the

later stages of plant growth and can last for

several months.

Tidal wetland rice is cultivated during the

wet season in scattered areas along the coastal

plains of Bangladesh, India, Indonesia,

Myanmar, Thailand, Vietnam, and West Africa.

Tidal rice can tolerate submergence caused by

flash floods or tidal fluctuations. Salt-tolerant

tidal rice is grown in areas where there is salt

water intrusion from the sea. The soils are of

various ages and are complex and diverse,

particularly in river floodplain areas. Many of

these alluvial sediments have undergone little

soil formation. Soil texture varies from medium

to fine. It is usually more coarse on natural

levees and finer in depressions and backswamps.

Although many soils are fertile, problem soils

such as peat, acid-sulfate, and saline soils occur,

particularly near coasts.

Predominant cropping systems

The cropping systems vary depending on the

time, depth, and duration of flooding. Most

varieties of rice can survive complete

submergence for only 3 to 4 d and some rainfed

lowland rice can survive up to 10 d. In floodprone

areas, rice is the only food crop that can be

grown during the rainy season (June to

November in most of Asia). There are four major

cultural conditions in the flood-prone

environments for which rice varieties are

selected: deepwater (up to 100 cm or more); very

Deepwater rice in Cambodia.

The rice plant and its ecology 23

deepwater (100–500 cm); tidal; and dry-season


Deepwater rice and floating rice are sown or

transplanted before the floodwaters rise and

flower near the time of maximum water depth.

Deepwater rice varieties are adapted to

maximum water depths of around 100 cm and

most can elongate 2–3 cm/d when flooded.

Floating rice varieties are those that elongate

very rapidly under submergence, sometimes up

to 20 cm per day. They are adapted to rapidly

rising water and very deeply flooded areas.

Tidal rice is cultivated in coastal zones

during the wet season. It can tolerate

submergence caused by tidal fluctuations or flash

floods. It should not elongate stems when

flooded since floodwaters recede within about 2

wk and the plants would fall over. Salt-tolerant

tidal rice is needed where salt water intrudes

from the sea. During the dry season, these lands

are too dry or saline for cropping.

Irrigated rice is grown in flood-prone areas

during the nonflood periods if irrigation is

available. It is called boro rice in Bangladesh and

India. Traditionally, boro rice was cultivated only

in local land depressions, where there was

sufficient residual water in the soil for a crop

during the dry season. However, with improved

irrigation, mainly from tube wells, boro rice is

now cultivated on many floodplains. Although

boro rice replaced some floating rice, there is

now progress in integrating both crops. Floating

rice has also been largely replaced by irrigated

rice in southern Vietnam.

In Bangladesh, deepwater rice farmers have

traditionally grown a wide range of crops after

the floods by seeding or planting onto the straw

of the deepwater rice crop. These crops include

pulses, oilseeds, spices, potato, onion, garlic,

wheat, and barley. Postflood and dry-season

cropping are now widely practiced in

Bangladesh, India, Myanmar, and Vietnam.

Preflood cropping, although not widespread,

includes mungbean, sesame, chili, and sorghum.

These crops, if successful, are harvested before

the main floods arrive. Sometimes jute or maize

is planted along with deepwater rice or just

before the deepwater rice crop is sown. In India,

farmers in many deepwater rice areas have

recently incorporated grain legumes (mainly

mungbean), sesame, maize, and sorghum into

their rotation. They grow these crops as a

mixture with deepwater rice on stored soil water

at the start of the wet season.


Wet-season nonirrigated rice yields range from

zero to 4.0 t/ha depending on the season,

location, and rice type. Floating rice yields are

usually low, from about 1.0 to 2.5 t/ha.

Deepwater rice yields higher than floating rice,

sometimes up to 4 t/ha, and generates high

profits because of low production costs.

Submergence-tolerant varieties are grown in

more favorable areas and produce relatively high

yields if flash floods are not severe. Yields of

tidal rice vary widely and crop failure can occur

in salt-affected areas.

Production constraints

Although fertilizer tends to increase nonirrigated

rice yields, the response is often irregular

because of environmental stresses. As a

consequence, fertilizer use is limited and yields

are also low compared with irrigated rice, which

has controlled water supplies and high inputs of

fertilizer and pesticides.

There are many opportunities for increasing

the rice yields of the flood-prone ecosystem. The

yield potential of deepwater rice could be

improved by introducing an appropriate plant

type. Yields of flash-flood and tidal areas could

be increased by incorporating increased tolerance

for submergence, salinity, and acidity. Varieties

with tolerance for cold at the seedling stage and

in the early vegetative stage could increase boro

rice yield. However, yield increases for floating

rice through varietal improvement are more

difficult because survival is the first


Enemies and friends


Rice fields harbor a tremendous diversity of

animals, plants, and microorganisms, some of

which are harmful to the rice crop and many of

which are beneficial. The goal of many scientists

at IRRI and other institutions is to manage rice

pests in ways that are safe, sustainable, and

economical. Emphasis is placed on breeding rice

varieties with resistance to insect pests and diseases

and on minimizing the use of pesticides to

promote natural biological control by beneficial

24 Rice almanac

insects, spiders, and microorganisms. The

importance of biological control in rice was

dramatically demonstrated in the 1970s, when

the indiscriminate use of broad-spectrum insecticides

devastated populations of beneficial insects

and spiders and led to huge outbreaks of the

brown planthopper, which had previously been a

minor pest.

A rice pest is any organism that causes

economic loss in rice production, including

arthropods (insects and mites), pathogens

(bacteria, fungi, and viruses), weeds, mollusks

(snails), and vertebrates (rodents and birds).

Some common pests are shown in Table 3. The

damage they do ranges from severing stems or

killing tissue to competing with the crop for

nutrients and sunlight.

A recent survey found that rice pests in

tropical Asia cause an average yield loss of 37%.

Weeds are the most important source of loss:

weeds taller than the rice plants caused 23%

yield loss and weeds below the canopy 21%. The

most damaging diseases are sheath blight, brown

spot, and leaf blast, each causing 5–6% loss. The

most important insect pests are stem borers, with

damage at the reproductive stage causing 2.3%

yield loss.

Weeds are an almost universal companion of

rice in the tropics. In many situations, weed

growth is prolific and weeds are a major

constraint to crop yield. Weeding is a major

production cost, with estimates of 50–150 person-days

per hectare required for manual

weeding, depending on the number of weedings

and type of rice culture. For many farmers,

weeding requires the greatest labor input during

the agricultural cycle, and labor is often not

available when weeds are most damaging to the

crop. Upland rice more than any other crop

shows the ravages of a lack of proper weeding.

Sometimes, when the land is too weedy, the crop

is abandoned.

The demands of transplanting and manual

weeding and increasing shortages of labor have

encouraged the move to direct seeding in

irrigated and rainfed lowlands. Weeds become a

major problem in these systems because rice and

weeds emerge at the same time, and weed

control by flooding is difficult in seeded rice.

Herbicides are being used more to control weeds,

and herbicide-resistant weeds and pollution are

emerging problems in direct-seeded systems.

Table 3. Examples of organisms that may harm or

compete with the rice crop.

Insect pests

Stem borers

African rice gall midge

Yellow stem borer

White stem borer

Striped stem borer

Dark-headed rice borer


Rice leaffolders

Rice caseworm


Green leafhopper


Brown planthopper



Rice bugs

Malayan black

rice bug

Rice grain bug


Rice field rats

Orseolia oryzivora (Harris &


Scirpophaga incertulas


Scirpophaga innotata (Walker)

Chilo suppressalis (Walker)

Chilo polychrysus (Meyrick)

Cnaphalocrocis medinalis

(Guenée) and others

Nymphula depunctalis


Nephotettix virescens (Distant)

N. nigropictus (Stål)

N. parvus Ishihara et Kawase

N. cincticeps (Uhler)

Nilaparvata lugens (Stål)

Sogatella furcifera Horvath

Scotinophara coarctata


Leptocorisa oratorius


Rattus argentiventer

(Rob. & Kloss)

R. tanezumi (Temminck)


Viral diseases and their vectors

Rice tungro

Nephotettix virescens (Distant)

N. nigropictus (Stål)

Ragged stunt

Nilaparvata lugens (Stål)

Rice yellow mottle Chaetocnema pulla Chapius

Trichispa sericia (Guérin)

Bacterial diseases and their causal agents

Bacterial blight Xanthomonas oryzae pv.

oryzae (Uyeda ex Ishiyama


Swings et al 1990

Fungal diseases and their causal agents


Pyricularia oryzae Cav.

Sheath blight

Rhizoctonia solani

(Thanatephorus cucumeris

[Frank] Donk)


Ageratum conyzoides L.

Cyperus difformis L.

Cyperus iria L.

Echinochloa colona (L.) Link

Echinochloa crus-galli (L.) P. Beauv.

Fimbristylis miliacea (L.) Vahl

Monochoria vaginalis (Burm. f.) Presl

The rice plant and its ecology 25

Insects attack all parts of the rice plant.

Hundreds of species feed on rice, but only a few

cause yield loss. The most important and widely

distributed pest species are stem borers,

leaffolders, planthoppers, and gall midge. Stem

borers are chronic pests, found in every field in

every season, but generally at low levels.

Planthoppers and gall midge usually create

localized outbreaks, causing high yield losses in

relatively small areas. Biological control by natural

enemies plays a critical role in the

management of all insect pests. Resistant rice

varieties are of importance in the control of

planthoppers and gall midge. No strong sources

of resistance to stem borers have been found in

rice germplasm, although modern semidwarf rice

varieties generally have lower levels of stem

borer damage than the traditional varieties they

replaced. Insecticides are used extensively

against planthoppers in temperate areas of Asia,

where mass immigration of planthoppers from

tropical areas is a frequent problem.

Bacterial blight, blast, and sheath blight are

the most important diseases of rice and have a

worldwide distribution. Three insect-vectored

viral diseases are also of importance: tungro in

Asia, hoja blanca in South America, and rice

yellow mottle in Africa. Bacterial blight and

blast have been successfully controlled by

resistant varieties for many years. However, the

evolution of resistance-breaking strains of these

pathogens has necessitated the continuing release

of new resistant varieties. Strong sources of

resistance for sheath blight have not been

identified in rice germplasm. Sheath blight is a

particularly important disease in intensive ricegrowing

conditions where high levels of nitrogen

fertilizer are applied.

Integrated pest management

Modern approaches to crop protection rely on

management rather than control or eradication.

In this approach, a pest species is considered a

pest only when it reaches numbers that can cause

yield reduction. Natural factors—such as natural

enemies—that prevent pest populations from

increasing are emphasized. Indeed, most

organisms inhabiting rice fields are never

harmful. In addition, the use of rice cultivars that

are resistant to major pest species is encouraged.

These cultivars do not need prophylactic

treatment to control the insects or diseases to

which they are resistant. Using a combination of

control tactics instead of relying on just one

tactic, such as host-plant resistance or pesticides,

and basing the decisions for control on sound

economic grounds is called integrated pest

management or IPM.

Pesticides should be used only as a last

resort to bring abnormal pest densities down

when crop loss is expected to exceed the cost of

treatment. Pesticides are costly to farmers, can

disrupt natural biological control, and are

damaging to human health and the environment.

In Thailand, for example, it is estimated that

40,000 rice farmers suffer from varying degrees

of pesticide poisoning every year. In the

Philippines, there is a similar high level of

poisoning and the overall cost of crop loss from

pests is less than the farmers’ resulting health

costs. The total extra costs of pesticide use in

Thailand, including health, monitoring, research,

regulation, and extension, amount to $128

million per year.

Environmental effects are also serious in

Thailand, where pesticide residues are found in

nearly all samples of soils, river sediment, fish,

and shellfish. One survey found organophosphorus

insecticide residues in three-quarters

of tangerine samples and one-third of all

vegetable samples.

Farmer education is a central feature of

IPM, and various approaches have been

employed. Many countries have implemented

“farmer field schools,” which entail season-long

weekly meetings in which farmers learn about

the value of natural enemies and other aspects of

growing a healthy crop. Another approach is the

mass communication of “simple rules” to

farmers. A campaign to encourage farmers to

experiment in eliminating early season

insecticide applications has been very successful

in Vietnam and is now being attempted in

Thailand. The campaign used billboards, cartoon

characters, information handouts, and humorous

radio programs; it reduced rice farmers’

insecticide use by an estimated 70% and the

proportion of farmers believing that insecticides

bring higher yields fell from more than 80% to

just 13%.

Landscape manipulation is a new approach

to IPM. The concept of using alterations to the

rice field and its surrounding areas involves the

roles of bordering vegetation and levees, and

26 Rice almanac

Predator movements

between habitats

Aquatic predators, frogs

Control mechanisms



of pyralids


of hoppers






Rats, leaf-feeding insects,

pathogens, snails, weeds

Pest movements

across habitats

Fig. 7. Landscape features and organism associations of the rice ecosystems.

patterns of distribution of pests and their natural

enemies in rice and nonrice habitats, within rice

fields and between the edges and interiors of rice

fields. Some of these associations are shown in

Figure 7.

Another biodiversity-based approach,

varietal mixtures, has been implemented to

manage blast disease in Yunnan Province, China.

Blast was causing a great yield loss in traditional

glutinous rice varieties and farmers were

spraying fungicides up to seven times on one

crop. IRRI scientists introduced the concept of

varietal diversification and worked with

scientists and farmers in China to practice the

interplanting of glutinous varieties with blastresistant

semidwarf varieties. This added diversity

of varieties prevented the fungus from

achieving the population explosions that had

previously occurred in the monoculture fields of

the glutinous varieties. The result has been

dramatic, in terms of both increased yield and

reduced use of fungicide. The interplanting

methodology is spreading like wildfire across

Yunnan Province and has great potential for application

in other areas of Asia.

New biotechnology-based approaches are

being applied to produce new insect- and

disease-resistant varieties. DNA marker-assisted

selection has been used to increase the efficiency

of breeding for pest resistance and to enable the

“pyramiding” of multiple genes for resistance to

a single insect or disease. Wide hybridization

techniques enable resistance genes to be

introduced from wild rice species. Genetic

The rice plant and its ecology 27

engineering is being employed to introduce

resistance to stem borers and sheath blight, two

pests for which limited resistance has been found

in rice germplasm. Details are given in the

section on “Biotechnology issues”.

More sustainable integrated weed

management technology is also being developed

by investigating and promoting rice cultivars

with superior weed competitiveness, biological

control, rice allelopathy, and a thorough

understanding of the biology and ecology of

weeds, and of the socioeconomics of weed

management practices of farmers. Integrated

weed management, promoting biological and

cultural control, and minimizing the use of

herbicides are seen as keys to sustainable ricefarming



As mentioned, most of the organisms in a rice

field are not harmful. Control of insect pests, for

example, depends on the activities of a whole

array of their natural enemies, through a complex

and rich food web of generalist and specialist

predators and parasites that live above, below,

and at the water surface as well as in flooded and

aerated soil habitats (Fig. 8). In tropical rice

fields, levees or bunds also form refuges for

early season predators of rice pests, such as ants

and spiders, as do bordering grasses and other

nearby habitats.

Predators are the most conspicuous group of

rice “friends,” that is, the natural enemies of rice

pests. They are the most abundant forms and are

often confused with pests. Some, such as spiders,

predatory crickets, longhorned grasshoppers,

damselflies, ants, wasps, and beetles, search the

plant for prey such as leafhoppers, planthoppers,

moths, caterpillars, and larvae of stem borers.

Some predators eat eggs of pests. Others, such as

water bugs and beetles, live on the surface of and

in the water in the rice field and attack pests that

fall from the plants.






Fig. 8. Habitat zones and dominant taxa of an irrigated rice farmer’s rice field in Calauan, Laguna,

Philippines. Canopy taxa are Stilbus sp. adults (1), Chironomidae adults (2), Cardiochiles philippinensis adults

(3), and Egadroma sp. adults (4). Neustonic (water surface) taxa are Microvelia atrolineata adults (5),

Ephydra sp. immatures (6), Entomobryidae adults (7), and M. atrolineata immatures (8). Planktonic and

benthic taxa are Heterocypris luzonensis (9), Eucyclops serrulatus adults (10), Chironomidae immatures (11),

and Hydrophilidae adults (12).

28 Rice almanac

Wolf spiders feed on a range of insect pests.

Spiders are especially numerous and diverse

partners in rice fields. In South and Southeast

Asia, at least 340 species are known from rice

lands. Parasitoids are generally more hostspecific

than predators. Although parasitoids are

easy to overlook, their effect on pests can be

extremely important. Parasitoids lay their eggs

in, on, or near the host. When the egg hatches

and the young parasitoid develops, the host

eventually stops feeding and dies. Various pathogenic

microorganisms (fungi, bacteria, and

viruses) infect and kill insect pests of rice. Other

species of fungi and bacteria attack weeds or are

important in the biological control of rice


The rice plant and its ecology 29

International issues

Past scientific research on various aspects of

rice cultivation and on the rice plant itself

has been responsible for remarkable gains

in the productivity of rice-farming systems.

However, rice production must increase if it is to

keep pace with population growth. The scope for

expansion of rice-growing areas is limited. Most

of the increase will have to come from improved

plants and from production methods that are

more efficient yet more environmentally


Here, we look at several major issues:

dealing with a future in which less water is

available, ways to increase the yield potential of

the rice plant, steps toward making rice more

nutritious, forecasting and dealing with the

effects on rice plants and ecosystems of global

climate change, reducing greenhouse gas

emissions from rice fields, the new research area

of functional genomics, biotechnology, and

integrating knowledge through crop modeling.

The looming water crisis

The amount of water needed to produce one ton

of rice would fill between two and three

Olympic-sized swimming pools.

Nearly 90% of fresh water diverted for

human use in Asia goes to agriculture and, of

this, more than 50% is used to irrigate rice.

China’s Yellow River, which flows for 4,600 km

through some of Asia’s richest farmland, has run

dry nearly every year since 1972. In South Asia,

the Ganges and Indus rivers have almost no

outflow to the sea in the dry season.

Too much water or too little

Asia’s water problems are caused partly by the

uneven distribution of water. On the one hand,

about half of China receives less than 400 mm of

rainfall a year, and extensive areas of

northwestern, central, and southern Asia are

drought-prone. On the other hand, the Ifugao rice

Precious irrigation water in Bangladesh.

International issues 31

terraces of the northern Philippines are situated

in one of the wettest rice-growing regions of the

world, with an average annual rainfall of 3,530


As a further complication, when rain comes

in Asia it usually arrives in torrents over a short

period, during a single monsoon that lasts from 4

to 6 mo. The rest of the year is almost dry. As a

result, much of the runoff simply flows into the

ocean as waste, at the same time eroding the

uplands, sometimes catastrophically. Furthermore,

the monsoon is often erratic, so that, in

many countries, floods and seasonal water

shortages occur concurrently.

Environmental costs of increased

rice production

Water was a critical input to the Green

Revolution, through irrigation, flood control, and

drainage, and it has contributed most to the

growth in rice production for the past 30 years.

But this expansion has occurred at a cost to the

environment: a proportion of the chemicals

applied as fertilizer and for pest and weed

control pollutes rivers and lakes through runoff

or groundwater through leaching.

In some upland areas, intensive agricultural

practices, coupled with deforestation, have

resulted in high rates of soil erosion and degradation

of both land and water resources in lowlands

below. The effects can reach as far as coastal

waters, with a consequent effect on riverine and

marine life.

Another problem involves long-standing

surface water, which causes waterlogging, makes

the land unproductive, and leaves soils salty as

the water evaporates. In India, about 6 million ha

of irrigated land are known to be affected by

waterlogging. Nearly 10% of Pakistan’s irrigated

13.5 million ha is estimated to be affected by

salinity, and northwestern India and northeastern

China are similarly degraded.

Overexploitation of tube and shallow wells

also presents problems. This is the case in large

areas of India, Pakistan, and Bangladesh. The

practice causes shortages of drinking water and

pollution when aquifers are recharged with

irrigation water contaminated with chemicals.

Capital costs of irrigation systems have

recently soared. In Sri Lanka, it cost almost three

times as much per hectare of land to set up an

irrigation system in the 1990s as it did in the

1960s, twice as much in India and Indonesia, and

nearly 50% more in the Philippines and Thailand.

At the same time, market prices for rice

have plummeted by nearly 40% over the past 30

years, while political pressure from

environmental groups against large-scale projects

is mounting.

What this will mean for future rice

production is that it will depend heavily on the

development of water-efficient measures

producing more rice per unit of water input. The

trend now is to develop management policies for

the efficient operation of irrigation systems;

technologies that reduce water consumption;

changes in the rice plant itself and the ways in

which it is grown, so as to use water more

efficiently; and to provide economic incentives

to farmers to reduce water losses.

Aerobic rice

One way to save water is to make a rice plant

that needs less of it. IRRI scientists are working

on creating a high-yielding tropical rice plant

that grows on dry but irrigated land instead of in

flooded paddies, calling it “aerobic rice.” An

Aerobic Rice Working Group has been formed,

consisting of plant breeders, physiologists, and

water and soil scientists, to address the many

difficulties of taking the plant out of its natural

environment and growing it as a dryland crop

like maize. Some upland rice varieties already

withstand drought but they are low-yielding and

do not respond to fertilizers.

A first step has been testing aerobic

varieties, already used commercially in Brazil

and experimentally in China, in tropical

conditions. In Brazil, the aerobic rice crops are

rotated with other crops. However, when the

plants are used as a single crop, as on most Asian

farms, yields fall dramatically after the first few

seasons, a phenomenon called “yield collapse.”

This is the major problem that the research is

now addressing.

Dry seeding—which can avoid the waste of

400–600 mm of rainfall—is assuming an

important role in rice production in rainfed areas.

The early harvest of dry-seeded rice can allow

planting of a second crop, which makes use of

rainwater that arrives later in the season. This

practice also reduces risk of drought where the

rainy season is short, and because dry-seeded

cultivars can generate more roots.

32 Rice almanac

Aerobic rice cropping is not an option in

semiarid to arid climates, nor on saline and acidsulfate

soils. Removal of a permanent water

layer and thereby reduced percolation could

result in soil degradation such as salinization,

alkalinization, and acidification. Water-saving

efforts under these conditions concentrate on the

replacement of long- and medium-duration

varieties by short-duration varieties and on good

water management (e.g., irrigation stops 2 weeks

before maturity).

In the Sahel, short duration has been a target

for introduction and breeding for some time. In

the mid-1990s, cultivar Sahel 108 was

introduced and quickly proved popular,

occupying one-third of the rice area of the

Senegal side of the Senegal River Valley in the

wet season and two-thirds in the dry season, and

up to a third of the area on the Mauritanian side

of the river in 1999. It thus saves at least 11

million m 3 of water use by plants; at 40%

irrigation efficiency, this amounts to 28 million

m 3 , or $400,000 in saved fuel costs for pumping.

The water-weed connection

One reason farmers keep rice fields continuously

flooded is to keep down weeds, which compete

less well with rice under such conditions. But if

flooding is reduced, other ways of controlling

weeds will be necessary.

Scientists are now examining the place of

weeds in the entire rice-growing system, with the

aim not simply of attacking and killing them by

one means or another, but of managing them in a

way that will not interfere unduly with rice

production. This involves studying the interaction

of such components as water, tillage

practices, and weeds, and incorporating in the

rice plant characteristics that increase

competitiveness with weeds, such as early vigor.

It also involves investigating naturally occurring

pathogens of weeds and how they might be used

to suppress weed growth.

By such means, scientists at CIAT, IRRI,

and WARDA are developing environmentally

sound integrated weed management systems that

they hope will prevent the kind of excessive

reliance on chemical herbicides that happened

with insecticides a decade or so ago. Meanwhile,

herbicides remain an important component of

integrated weed management and their use is

rising rapidly. At the same time, weed resistance

to them is increasing. Up to 15 major weed types

now show such resistance and strategies are

needed that minimize herbicide use and promote

the development of further resistance.

A new research initiative

So important is the water problem worldwide

that the Consultative Group on International

Agricultural Research (CGIAR)—a consortium

of donors supporting 16 international research

centers including CIAT, IRRI, and WARDA—

has mounted a water conservation campaign. The

International Water Management Institute and

several other CGIAR and national research

centers are investigating the effects of on-farm

water management on system performance

through a network called SWIM—Systemwide

Initiative on Water Management. The objective is

to enhance the productivity of water in an

environment of growing scarcity and

competition. The result is expected to include not

only ways to increase water productivity but also

the development of methods to measure water

productivity that will be widely adopted by

researchers and the building of research capacity

in water management. The main focus of SWIM

is a comprehensive assessment of the benefits,

costs, and future directions of irrigated


Adding protein, vitamin A, and

other micronutrients

Vitamin A is one of the most important nutrients

in maintaining life and health. Consequently,

dietary lack or deficiency of this vitamin leads to

severe clinical symptoms. Africa, Asia, and Latin

America and the Caribbean have areas where this

is a severe problem. Overall, around half a

million children become irreversibly blind each

year as a result of vitamin-A deficiency. A much

larger number of children develop other eye

problems—5 million children per year in

Southeast Asia alone. Worldwide, an estimated

124 million children are deficient in vitamin A to

some extent, and improved intake would prevent

1–2 million deaths each year of 1- to 4-year-old


IRRI is joining an international research

endeavor to find out whether rice consumption

can help prevent this problem. The research has

been made possible by the development in

European laboratories of Golden Rice, a

genetically modified rice variety that contains

International issues 33

precursors of vitamin A—beta-carotene and

other carotenoids—in its seeds. Rice plants

already have the pathway for producing betacarotene

in their vegetative tissues; by genetic

engineering, genes for beta-carotene driven by

endosperm-specific promoters express betacarotene

(provitamin A) in rice seeds.

National institutes and IRRI are working

together in finding suitable, well-known local

varieties in which to transfer the new pathway.

The resulting new lines will be released to

national agricultural research centers, which will

undertake their own research on the safety and

effectiveness of these vitamin-enriched varieties

in combating vitamin-A deficiency. Each country

will make its own evaluation.

The interspecific varieties (NERICAs)

recently developed by WARDA for West African

upland ecologies have a higher protein content

than either of their parent varieties. They

therefore have the potential to improve the

nutritional status of the subsistence-oriented

farming families who are their target


Another new rice variety, one that is

particularly rich in iron and zinc, is awaiting a

large-scale nutrition trial in the Philippines. This

variety is not transgenic and was developed by

exploiting natural variation in rice germplasm.

Iron and zinc are usually deficient in people

eating a rice-heavy diet. Lack of iron causes

widespread anemia in some countries. Zinc

enhances the body’s capacity to absorb iron and

combats diarrhea and cholesterol accumulation

in blood vessels. The new variety, developed by

IRRI, was tested by a group of 27 religious

sisters in Manila, who ate the rice exclusively for

six months, resulting in higher iron levels in their

blood. However, a larger sample is needed to

verify the results and a new trial involving 300

persons is beginning, under the supervision of

two U.S. universities. The trials are organized by

the International Food Policy Research Institute

in Washington, D.C.

Potentially, these two new rice varieties can

help prevent some of the most widespread

micronutrient deficiencies in Asia.

Increasing yield potential

Since the late 1980s, scientists from IRRI and

other institutions have been developing a new

rice plant architecture, one that would increase

yield potential in the tropics from 10 to 12 t/ha

per crop: a fast-growing plant with a deep root

system, dark green erect leaves, and 200 to 250

grains per panicle. It has been a massive task; for

example, a grain-filling problem took three years

of breeding effort to solve. When the number of

tillers had to be increased to deliver a bigger

harvest, the program adjusted to the new goal.

Work on the plant is nearing fruition and in

temperate China it is showing yields of 13 t/ha.

Lines have been developed with resistance to

various pests and diseases. Breeders in different

countries are selecting lines best suited for local

conditions and multiplying seeds for distribution.

It may be four more years before they are

available to farmers.

Meanwhile, global warming is creating new

problems for rice farming and plants are needed

that not only are higher yielding but also will

thrive in higher temperatures, with more carbon

dioxide and pollutants in the air, and where

extremes of weather are commonplace. The

plants will have to use less water and use nitrogenous

nutrients very efficiently. This is an even

more challenging task. There are biophysical

limits to how much grain rice plants can produce,

imposed by the photosynthetic pathway they use

to convert sunlight into organic matter. Only by

changing that pathway can the limit be


C 4


In an attempt to improve yields, scientists from

several research centers in both developed and

developing countries are beginning work to

modify the photosynthetic pathway of rice plants

from a C 3

to a C 4

system such as is found in

maize, a more efficient user of sunlight. Most, if

not all, of the genes required for a C 4


actually exist in the rice plant, but they are

expressed differently. Importantly, C 4

-type plants

operate well at high temperatures, are extremely

water-efficient, and require less nitrogen, and it

might be these characteristics that will be most

important in a world of climate change. It is

something of an enigma that rice does not

already operate on a C 4

system, given the

advantages of that system. As carbon dioxide

levels increase in the future, the yield gap between

a C 3

plant and a C 4

plant will close, but the

difference in water-use efficiencies will widen.

Nonetheless, this is unlikely to happen before the

end of the 21st century. Improving rice

34 Rice almanac

International Rice Information System

The International Rice Information System

(IRIS) is a database for managing and integrating

information on genetic resources,

phenotypic and molecular characterization,

crop improvement, and crop management.

Although major international initiatives for

germplasm collection and conservation

followed the Green Revolution, much

collected material is still not used because

information about it is difficult to access

and is not integrated with other data

sources. As a result, its potential impact on

agriculture has not yet been realized. The

sheer volume of unmanaged genealogical

information produced by plant scientists

precluded its wide use until now.

IRIS is the implementation for rice of the

International Crop Information System

(ICIS), which is being developed by

scientists of several CGIAR centers,

national agricultural research and extension

systems, and research institutes to

address this constraint for different crops.

The core of ICIS is a genealogy

management system that facilitates the

unique identification of germplasm and

manages synonyms and homonyms. It

allows users to trace cultivars back to their

ancestral landraces or to lines of unknown

pedigree; genealogies are automatically

updated as additional information on

ancestors is discovered. This information

can be accessed not only as text but also

as family trees—genealogical dendrograms.

The genealogy management system links to

a data management system, which integrates

data from different scientific

disciplines and will provide new insights

into crop adaptation. Geographical

information about germplasm evaluation

sites is associated with latitude and

longitude and can be analyzed with

geographic information systems.

For more information on IRIS, see

photosynthesis may be the only way to

guarantee feeding the growing population of

Asia over the next 50 years.

Hybrid rice

Hybrid vigor or heterosis is a universal phenomenon

that occurs in all biological systems. In

plant breeding, hybrid vigor denotes the

expression of more vigor than in the better parent

and the existing commercial variety.

Commercial exploitation of heterosis to

increase rice yields has been successfully

demonstrated in China, where nearly 18 million

ha of a total of 33 million ha of harvested rice

land were planted to F 1

hybrids by 1992. Rice

hybrids yield about 20% higher than do inbred

rice varieties.

Research in other countries also indicates

that heterosis in rice can increase yields by 15–

20% over those of the best available semidwarf

inbreds under irrigated conditions. Commercial

hybrids have been identified and/or developed

and grown on several hundred thousand hectares

in Vietnam, India, and the Philippines. Several

other countries are still searching for suitable

hybrids for commercial cultivation.

Cytoplasmic male sterility is the most

effective genetic tool for developing hybrid rice.

Photoperiod-sensitive and thermosensitive male

sterility systems have shown promise and have

resulted in some two-line commercial rice

hybrids in China. IRRI and some national

institutions are still developing these male

sterility systems. The use of chemically induced

male sterility has not been efficient enough for

deployment on a large scale.

Well-developed hybrid seed production

practices give average yields of 2 t/ha of seed.

Seed yields of 1–2 t/ha have been obtained by

commercial seed growers in India, Vietnam, and

the Philippines.

Tropical hybrid rice

The search for better tropical hybrids has

continued at IRRI for the past 20 years. The 15

commercially usable, male-sterile parental lines

bred to date have been designed for irrigated cultivation.

Experimental hybrids for rainfed

lowland systems have now been produced and

are being tested in India, the Philippines, and

Thailand. At the same time, new farm

management packages for the hybrids are being

developed. Private industry is showing

considerable interest in tropical hybrids to

become the provider of seed for each crop.

Farmers are wary of using hybrids: having to buy

seed for each crop means that their costs increase

by about $50 per hectare. But the increased

yields mean extra income of $135 to $200 per

hectare per crop.

International issues 35

Hybrid breeding has also begun with IRRI’s

new plant type and could give yields of up to 15

t/ha. Golden Rice hybrids are another possibility

for the future. An International Hybrid Rice

Network extends across Asia, involving national

research institutions in Bangladesh, China, India,

Indonesia, the Philippines, Sri Lanka, and


Researchers in China have used NERICA

lines (see section on “Interspecific rice” below)

as fertility restorers for cytoplasmic male-sterile

lines. Crosses proved that restoration was

controlled by a single dominant gene from the

NERICA lines.

Interspecific rice (“New Rice for

Africa,” or NERICA)

The potential of the cultivated rice species in

Africa (Oryza glaberrima) has been “unlocked”

through the successful crossing of this species

with O. sativa and the development of truebreeding

“interspecific hybrid progenies” (the

NERICA varieties). The yield potential of these

varieties is enhanced by the combination of the

African species’ adaptation to the West African

environment with yield attributes from O. sativa.

In addition, secondary branching on the panicles

(from O. sativa) combined with transgressive

segregation (a form of heterosis) gives NERICAs

more than 400 grains per panicle, compared with

about 250 in O. sativa. These new upland

varieties also combine noninput dependence with

input responsiveness—yielding more grain as

farmers earn more to invest in their crop.

Functional genomics

The rice plant has 12 chromosomes, the tiny

strands of DNA within each cell that hold its

genetic information. Along the chromosomes,

about 50,000 genes make up the genome.

Scientists have been working for several years on

rice gene sequencing: pinpointing each gene and

deciphering DNA sequence structure, variation,

and function. The study is called genomics. The

entire sequence of genes along the rice

chromosomes is being elucidated by various

groups. Syngenta, a multinational agribusiness

corporation, and the Beijing Genomics Institute

published their sequencing of the rice genome in

April 2002. The International Rice Genome

Sequencing Project led by Japan expects to

complete its task by the end of 2002. The

international project, largely supported by governments,

is committed to providing all sequence

information to the public.

The rice genome represents an enormous

pool of information for rice improvement

through marker-aided selection or genetic

transformation. However, a full application of

this wealth of information will not be possible

until the biological functions encoded by the

sequenced DNA are understood. Functional

genomics is the aspect of discovering what the

genes do: how they function, how their functions

combine with those of other genes, and for what

purpose. Thus, functional genomics is expected

to become the engine that drives discovery of

traits and helps solve presently intractable

problems in crop production.

IRRI is in a unique position to contribute to

this study, backed by the vast collection of rice

germplasm that it holds in trust.

One approach to the task is to delete a

particular gene from the plant using chemicals or

irradiation, then examine the plant for missing

characteristics as it grows. IRRI already has a

collection of more than 18,000 of these “deletion

mutants” and the number is growing rapidly. The

Institute is also developing a large collection of

“introgression lines,” plants that carry a wide

range of chromosome segments implanted from

commercially used varieties and wild rice. These

will be used in the discovery of the functional

diversity of the genes, and to understand the

overall genetic, biochemical, and physiological

systems in the plant. The mutants and

introgression lines can be supplied to other

institutions to assist them in the challenging

work of assigning functions to the rice genes.

So far, the functional genomics team at IRRI

has identified several genes giving the plants

enhanced resistance to various types of

pathogens that cause diseases. The team has also

produced plants containing small chromosome

segments from wild rice that confer resistance to

several diseases and pests. In fact, more than 100

genes that can help the plants defend themselves

against pathogens have been found and are

already being used to select better diseaseresistant

varieties. The scientists have also found

introgression lines and mutants that exhibit

variations in growth and yield under water stress.

Such genetic variation is the prerequisite for

selecting better performing germplasm in soil

with too much or too little water. Scientists also

36 Rice almanac

studied the drought response of the plants in

different water conditions and identified a

variety of proteins produced by the plant in

response to drought and salinity stress.

A new tool under development for the work

is the “microarray,” in which about 20,000 genes

can be displayed at once on a “chip,” which can

then be used as a sensor to detect genetic

messages that are turned on or off when plants

are exposed to stress. Thus, the expression of the

genes can be recorded and analyzed to give a

total picture of how the plant behaves in different

conditions. In this way, scientists will be able to

identify hundreds or perhaps thousands of genes

that may combine and interact to achieve a

particular function, such as tolerating drought,

resisting disease, or producing more nutritious

grains. This technology speeds up the discovery

of gene functions enormously, doing in weeks

what would have previously taken years.

Details of the methods used in functional

genomics are given in the section on

“Biotechnology issues” later.

Functional genomics requires diverse

genetic resources, expertise in evaluating and

identifying important traits, and an extensive

collaborative network to evaluate newly found

traits in different environments. Broad participation

by the rice research community is needed to

realize the potential offered by genomics.

To meet this need, the International Rice

Functional Genomics Working Group has been

formed to

• build a research community with a shared

vision on rice functional genomics,

• create a common resource platform to

broaden access to new knowledge and

tools in functional genomics, and

• accelerate the application of functional

genomics to rice improvement.

Three activities are being given high priority

by this rice research group:

1. Creating a vehicle to communicate

information related to functional genomics.

2. Promoting the sharing of genetic stocks.

3. Facilitating the sharing of resources for


So far, 13 research groups have joined the

effort and national research centers in particular

are sought to become involved. More

information can be found at


Of paramount importance is protecting the

interests of rice farmers and consumers by

ensuring that all information is available to the

public and not locked up in private companies or

even universities and public institutions,

exercising their “intellectual property rights.” As

part of the effort to broaden access to the

information, IRRI has launched a database on the

Internet that describes the biological

characteristics of the collection of deletion

mutants; a similar database has been developed

for information on stress-response genes. These

will be linked to genome sequence databases to

improve information exchange.

Ultimately, plant breeders may be able to

find in a database the genes they need to achieve

particular traits, select the genes from the

genome map, and mix them as required to

produce the desired plant type.

Global climate change

and rice

Climate change is not a new phenomenon.

Change has been a consistent feature of Earth’s

climate. Periods of relatively cool temperatures

caused the Ice Age. For the past 10,000 years,

however, Earth has experienced the longest

period of consistently warm temperatures since

the beginning of life. That warm period almost

exactly matches the period over which modern

agriculture has evolved.

For the first time in history, climate appears

to be changing as a direct result of human

activity. People have released chlorofluorocarbons

into the atmosphere, thereby degrading

stratospheric ozone and increasing biologically

harmful ultraviolet (UV) radiation that reaches

Earth’s surface. Through mining and combustion

of fossil fuels, deforestation, maintenance of

livestock herds, and even through rice

cultivation, people have released enormous

quantities of carbon dioxide (CO 2

), methane

(CH 4

), and other “greenhouse” gases into the


Samples from ice cores show that past

fluctuations in global temperatures were strongly

correlated with concentrations of atmospheric

CO 2

. Simulation models of global atmospheric

circulation predict that greenhouse gases will

cause a 2–8 °C global temperature rise before the

end of the 21st century.

International issues 37

UV radiation effects

UV-B radiation damages leaf tissues in rice

seedlings. Leaves become stunted, stomata

collapse, and photosynthesis decreases. Some

rice varieties appear to be better able than others

to withstand the adverse effects of UV radiation.

Leaves of tolerant varieties contain phenolic

compounds, which are natural chemicals that

filter out harmful UV-B radiation before it can

damage sensitive tissues. Research is now in

progress to predict possible regional losses in

rice productivity if UV-B radiation continues to

increase, and whether plant breeders can prevent

those yield losses by developing new varieties

that tolerate UV radiation.

In addition to its adverse direct effects on

rice plants, UV-B may change the susceptibility

to and/or tolerance for disease. Although there is

no evidence yet that UV-B affects susceptibility

to blast, it appears that the tolerance for blast

decreases. In other words, UV-B does not

increase disease frequency, but enhances the

effects of disease on plant growth.

Global warming

Although increasing atmospheric CO 2


plant growth, the beneficial effects on rice

growth have been observed for levels up to only

500 ppm. Some plant species respond positively

to CO 2

levels up to 1,000 ppm. Experts predict

that atmospheric CO 2

will surpass 650 ppm

before the end of the 21st century. Furthermore,

the benefits of increased CO 2

would be lost if

temperatures also rise. That is because increased

temperature shortens the period over which rice

grows. Research is being conducted to identify

means by which rice plants may better benefit

from increases in atmospheric CO 2


minimizing the adverse effects of warmer

temperatures (Fig. 1).

Emissions of greenhouse gases

from rice fields

Methane (CH 4

) is second in importance to CO 2

as a greenhouse gas. CH 4

concentration in the

atmosphere has more than doubled during the

last 200 years. Some of this CH 4

is produced by

rice fields (Fig. 2). To reduce the burden and

harmful effects of CH 4

in the atmosphere, emissions

from all anthropogenic sources have to be


Methane is produced in the anaerobic

conditions associated with submerged soils.

Much of it escapes from the soil to the

atmosphere via gas spaces in rice roots. The

remainder bubbles up from the soil or diffuses

slowly through the soil and overlying floodwater.

The potential for CH 4

emissions from rice

fields has long been noted, but comprehensive

measurements of CH 4

fluxes in rice fields have

been reported only since the early 1990s. Water

regime, organic matter management,

temperature, and soil properties as well as rice

plants are the major factors determining the

production and flux of CH 4

in rice fields.

Irrigated rice areas are the major source of CH 4

emissions from rice fields. The assured water

supply and control, intensive soil preparation,

and resultant improved growth of rice favor CH 4

production and emissions.

With financial support from the U.S.

Environmental Protection Agency, IRRI

undertook baseline research on CH 4

fluxes in rice

fields in collaboration with the Fraunhofer

Institute for Atmospheric Environmental Research,

Germany, and the Wetland

Biogeochemistry Institute of Louisiana State

University, USA. Other collaborating institutes

were the Wageningen Agricultural University,

The Netherlands; the Laboratory for Microbiology,

French Institute of Scientific Research for

Development Cooperation; the Université de

Provence, France; and the University of Georgia,

USA. IRRI also coordinated an interregional

research program on CH 4

emissions from rice

fields funded by the Global Environmental Facility

of the United Nations Development

Programme. This activity comprised

collaborative CH 4

research on irrigated, rainfed,

and deepwater rice in China, India, Indonesia,

the Philippines, and Thailand.

The studies, which took almost a decade of

work, concluded that CH 4

emissions from rice

fields are much smaller than originally thought,

contributing on the order of only 10% of total

global CH 4

emissions. High methane emissions

are associated with specific rice management

practices, and management practices can be

modified to reduce emissions without reducing


One result was the finding that CH 4

production from Indian rice production,

originally estimated to be some 38 million t per

38 Rice almanac


Chlorofluorocarbons attack the

stratospheric ozone layer


filters UV


Visible light

passes through



Heat trapped by greenhouse

gases warms Earth and

decreases rice productivity

in the tropics

Flooded rice fields

emit methane

Rice fields

Greenhouse gases in

atmosphere are increasing:

• carbon dioxide

• methane

• nitrous oxide

Carbon dioxide


rice growth

Fig. 1. How global climate change affects tropical rice. Greenhouse gases trap heat and warm Earth's

surface. Higher temperatures reduce the productivity of tropical rice. The two most important greenhouse

gases for rice are CO 2

, which may enhance rice growth, and CH 4

, which is emitted by flooded rice fields.

Degradation of the atmospheric ozone layer allows more biologically destructive UV-B radiation to reach

Earth's surface. The effects of UV-B on rice are not known.


(O 2



(CH 4




(CH 4


(CH 4





(CH 4


O 2

CO 2


(CH 4


Decomposition of

soil organic matter

Fig. 2. Methane gas escapes into the atmosphere from flooded rice fields in three ways. Up to 80% travels

through the plant from the roots. Ebullition, in which gas bubbles up to the water surface, and diffusion

each contribute smaller amounts.

International issues 39

year, was actually less than 19 million t, about

4% of the estimated global total. Without this

research, international protocols would have required

India to halve its rice cultivation in the

short term! Emissions in other countries are also

much less than estimated.

The research demonstrated ways to reduce

emissions without sacrificing yields, such as

• using intermittent drainage in irrigated

systems, at the same time saving water;

• improving crop residue management

through composting, mulching, etc.; and

• using direct seeding, at the same time

reducing water and labor requirements.

The project explored trade-offs between

mitigation technologies and socioeconomic

aspects and found that

• intermittent drainage in irrigated systems

reduces emissions and can also save water;

• improved crop residue management

through composting, mulching, and early

incorporation of organic manure can also

reduce emissions; and

• direct seeding results in less labor and

water input and at the same time reduces

methane emissions.

However, management practices that make

conditions less anaerobic favor production of

another greenhouse gas, nitrous oxide (N 2


which is 10 times more powerful in its

atmospheric warming potential than methane.

Agriculture is the main source of N 2

O emissions;

it is produced in the soil as an intermediate

product during microbial nitrification and

denitrification. Potential N 2

O emissions increases

when available N increases through, for

example, fertilization. Although N 2

O is not a

problem in continuously flooded systems, using

more aerobic rice-growing conditions or growing

aerobic rice could result in significant N 2


emissions. This is a new area for research.

Biotechnology issues

Some desired features of future improved rice

varieties are superior grain quality, higher yield

potential, enhanced resistance to pests and

diseases, and greater tolerance for stresses such

as drought, cold, and nutrient deficiencies.

Biotechnology is seen as perhaps the most important

new resource for achieving varietal

improvement (Table 1).

Table 1. Applications of biotechnology techniques to rice



Embryo rescue

Anther culture

Molecular marker-aided


DNA fingerprinting



protoplast, and

biolistic methods)


Transfer of genes from wild

rice to cultivated rice

Rapid stabilization of new


Acceleration of breeding

programs by use of

genetic markers rather

than phenotypic selection

Identification of genetic

variation in pests and


Introduction of novel genes

into rice

Rice biotechnology techniques encompass

plant tissue culture and molecular biology. Tissue

culture techniques such as embryo rescue and

anther culture have made important

contributions. Embryo rescue enables breeders to

attempt wide crosses between varieties that could

not be hybridized before; anther culture allows

faster stabilization of breeding lines. Molecular

techniques help to accelerate traditional breeding

programs through gene tagging, streamlined

germplasm management, and assessment of

population structures in insect pests and

pathogens through DNA fingerprinting.

Marker-assisted selection, for example, has

been used recently at IRRI to improve crops in

saline areas. Scientists developed a large number

of plants whose genetic tolerance for salinity was

proven by marker-assisted selection. The plants

are being designed specifically for use in

Bangladeshi coastal wetlands and are being

tested and further bred by farmers there under

supervision in their own fields.

After extensive study, a marker has been

identified linked to recessive major-gene

resistance to the devastating rice yellow mottle

virus (RYMV). RYMV is a major threat to

irrigated and lowland rice in West Africa, and

has also been found in East Africa. The way is

now open for marker-assisted selection of

resistant varieties.

40 Rice almanac

Anther (mid-uninucleate)


Mature seeds

Immature embryo

(8—12 days)

Transgenic rice


embryogenic calli (EC)



EC (selected)

Southern Western Enzymes





Protoplasts + DNA




Selection, 50 µg/mL

(2—3 wk) Hg/PPT

Plant regeneration

(with or without selection)


(8 wk) Hg/PPT

Transformed calli


Selection, 50 µg/mL

(4—6 wk) Hg/PPT


transformed EC

Fig. 3. A. schematic protocol for production of fertile transgenic rice plants using biolistic, protoplast, and

Agrobacterium systems.

But biotechnology’s most novel contribution

will probably be in adding alien genes to the rice

gene pool through genetic engineering. Genetic

engineering also allows the reintroduction of rice

genes that have been extracted and modified to

give altered properties. Such gene transfers are

impossible with conventional breeding methods.

Genetic engineering also allows introducing one

or two well-characterized genes at a time. There

is no need for the extensive backcrossing done in

conventional hybridization to remove

undesirable genes.

Three methods have been used successfully

to transfer genes into rice: protoplast transformation,

biolistics or particle bombardment, and

Agrobacterium-mediated gene transfer (see Fig.


Marker genes and promoters

The first foreign genes expressed in rice were

bacterial genes conferring antibiotic (HPT,

hygromycin phosphotransferase) or herbicide

resistance (ppt, phosphinotricin acetyl

transferase). When the appropriate antibiotic or

International issues 41

herbicide was present, these selected genes

permitted the few transformed cells to grow

while nontransformed cells died. It is evident

now that the HPT gene as a selectable marker

works very well in rice. HPT activity in rice cells

is detectable by an enzyme assay, which is

routinely used to screen transgenic plants.

Alternatively, a new nonantibiotic selection strategy

has been developed using mannose as a

selective agent and the pmi gene.

Reporter genes, such as the bacterial ß-glucuronidase

gene, have been used to optimize the

transformation protocol and to study the

properties of some new plant promoters that may

eventually be used to control the expression of

useful genes in transgenic rice.

A promoter is a segment of DNA that

precedes a gene and controls its activity by

instructing the enzyme RNA polymerase about

where, when, and how often to begin

transcription of messenger RNA. Some

promoters allow activation of their gene only in a

certain type of cell, at a particular stage of plant

development, or in response to a specific

external signal. Other promoters allow constitutive

expression of genes in a wide range of cell

types. The promoters most commonly used for

rice transformation belong to the last group

because most current experiments seek to

determine whether the gene of interest functions

at all in the transgenic situation.

Useful foreign genes

Now that substantial progress has been made on

transformation protocols for rice, numerous rice

lines with useful foreign genes have been produced.

Several insecticidal toxin genes from

Bacillus thuringiensis (Bt) have been transferred

to rice, including cry1Ab, cry1Ac, and cry2A.

The process is shown in Figure 3. Plants

containing Bt genes have been evaluated in

greenhouses in numerous countries and have

been field-tested in China. They have shown

substantial resistance to caterpillar pests such as

stem borers and leaffolders. Genes encoding

proteinase inhibitors from cowpea, soybean, and

potato have also been transferred to rice for

enhanced resistance to caterpillars. Rice has also

been transformed with a lectin gene from the

snowdrop plant that encodes a protein toxic to

the brown planthopper and green leafhopper.

Work is in progress with all these genes to

develop varieties suitable for farmers. For example,

the right doses and combinations of toxins

for particular pests must be identified and then

established in plants, the stability of toxin

production over several generations must be

verified, and the performance of the plants must

be evaluated under field conditions.

Golden Rice is the latest development in

using foreign genes (see also “International rice

research and development”). This rice, invented

by two German scientists, contains beta-carotene,

the precursor of vitamin A. The intention is

to combat vitamin-A deficiency, which is

responsible for blindness and death throughout

Asia. The plant was created by implanting in a

rice plant two genes from a daffodil and one

from a bacterium.

Sustainable use of transgenic plants

As is the case with all insecticides, insect pests

will eventually develop resistance to Bt toxins

and other foreign insecticidal proteins in rice.

However, this process can be slowed, and the

level of resistance stabilized, by careful design of

transgenic plants and the use of appropriate

strategies for the deployment of these plants in

farmers’ fields. The development of “resistance

management strategies” is a very active area of

research in entomology and encompasses studies

of insect behavior, ecology, and toxicology. Two

approaches receiving the most study are

combinations of multiple toxin genes within

varieties, such as a Bt toxin gene plus a

proteinase inhibitor gene, and the maintenance of

fields of rice that do not contain transgenic

plants, to preserve a “refuge” of insects not

selected for resistance to the toxins. In each

generation, insects from the refuge fields would

mate with resistant insects that survived in the

transgenic fields, maintaining the number of

resistant offspring at a low level.


Genetic engineering is a relatively new

technology and most countries closely regulate

the testing and commercial release of transgenic

organisms. The Philippines was the first country

in Southeast Asia to have biosafety guidelines.

The National Committee on Biosafety of the

Philippines (NCBP), established in 1990,

develops policies to regulate the use of

transgenic plants in the country, including those

42 Rice almanac

eing developed at IRRI. Similar biosafety

committees have been established in other ricegrowing

countries in Asia.

One of the principal biosafety issues is the

assessment of the movement of foreign genes by

pollen dispersal from transgenic rice to other rice

varieties and wild rice. In 1995, IRRI began

operating a greenhouse designed to prevent pollen

dispersal from transgenic plants in the early

stages of evaluation. This 320-m 2 greenhouse

enables researchers to grow and multiply

transgenic plants and to evaluate them for

resistance to insects, disease, and other stresses.

A recent study using transgenic IR72 with Xa21

in a screenhouse revealed that there was no

functional transfer of transgenes from transgenic

IR72 to nontransgenic control plants, a finding

that ensures the potential use of this technology

in improving rice germplasm.

Crop modeling to integrate


Crop modeling enables researchers to integrate

knowledge from different disciplines in a

quantitative way. That, in turn, helps researchers

to understand the underlying processes that

determine the behavior of complex agricultural

systems. Mathematical models are representations

of systems made from mathematical equations.

Integrating and solving the equations

enable a numerical description of the system to

be produced. During the first phase of a

modeling exercise, the modeler seeks to give

names, magnitudes, and units to the component

parts of the problem. In the second phase of

modeling a problem, the processes are described

as mathematical functions. In the final phase,

“what-if” questions can be asked about the

functioning of a system and numerical answers

provided. Mathematical models that contain no

clear logical link with the basic processes governing

the relationship between the system inputs

and outputs are unlikely to contribute much of

significance to any debate concerning strategic

decisions in relation to research management.

Models at different levels of detail are

developed to meet different objectives, ranging

from a thorough understanding of an existing

system to the prediction of crop production in

untested conditions. Four types of crop production

systems can be distinguished:

1. Potential production, where production is

determined by solar radiation,

temperature, and crop and varietal


Transgenic greenhouse at IRRI.

International issues 43

2. Water-limited production.

3. Water- and N-limited production.

4. Water-, N-, and other nutrient-limited


Going from type one to type four, production

generally decreases and the variables that

determine system behavior increase. At all

levels, growth-reducing factors such as insects,

pathogens, and weeds can be introduced. Models

for all production levels can be developed. Models

at the first level are further developed than

models at the others.

Well-developed models that simulate the

growth of a crop in relation to its dynamic

environment can be used to help prioritize

research. Crop modeling combined with

geographic information systems (GIS) analysis

enables researchers to distinguish agroecological

zones and to rank quantitatively the technical

constraints to agricultural production within

them. These models allow the impact of new

technology on agricultural production to be

assessed before the technology is introduced.

The GIS database can link the models directly

with socioeconomic aspects.

Crop simulation models have many uses.

Models can be used as a research tool and to

support problem solving, risk assessment, and

decision making. They can guide researchers in

prioritizing their research and in integrating

quantitative knowledge from different disciplines.

Also, models can be used as a framework

for training. Further, models can be used to

extrapolate research findings over broad regions

and extended time, since the models account for

crop-environment interactions. Using long-term

weather data, yield probabilities can be


Crop models are particularly useful in the

rainfed lowland rice ecosystem, which is

characterized by high temporal variability and

spatial heterogeneity of the environment. A

limited number of field experiments cannot

provide a reliable basis for management

strategies under the myriad conditions that exist.

Simulation models can replace expensive and

time-consuming experiments because of their

ability to generalize experimental findings and

help interpret the results of a few selected


An aspect that is beginning to gain more

importance is the use of models to set breeding

goals. The physiological attributes that

contribute significantly to crop production in a

given environment lend themselves to definition

by crop modeling. Models can serve to bridge

between functional genomics, ecophysiology,

and agronomy. Ecophysiological models are used

to analyze the influence of different plant

parameters (e.g., plant architecture, nutrient

status, partitioning) on desired agronomic traits

such as yield, weed competitiveness, or drought

tolerance. Functional genomics supplies genetic

markers for these traits, which then assist

breeders during the selection process.

Modeling can also improve crop

management. In West Africa, for example, a

framework was developed combining the use of

simulation models, field data, and long-term

weather data to design site-specific crop

management options. This helps farmers to

improve the timing of seeding, transplanting,

irrigation, and fertilizer application, as well as to

determine type and dose of fertilizer in a range of

biophysical and socioeconomic environments.

One component, a decision tool called RIDEV, is

already widely used by extension agencies in

Senegal and Mauritania.

Modeling is especially useful in yield gap

analysis, a method for identifying constraints to

agricultural production in different agroclimatic

zones. From yield gap analysis, constraints that

can be reduced can be identified. Researchers

then concentrate on ameliorating those factors

that contribute to the gap between farm yield,

potential farm yield, and potential experiment

station yield (Fig. 4).


station yield


farm yield

Yield gap 1


gap 2


farm yield








Fig. 4. Modeling applied to yield gap analysis helps

to identify constraints that can be reduced, thus

contributing to higher yields in farmers' fields.

44 Rice almanac

International rice research

and development

Research and development on rice are

carried out by many institutions in both

developed and developing rice-growing

countries. Internationally, three research centers

belonging to the Consultative Group on

International Agricultural Research (CGIAR)

have mandates to pursue research at the regional

or global level: the International Rice Research

Institute based in the Philippines, which is the

foremost global rice research center; the West

Africa Rice Development Association in Côte

d’Ivoire, responsible for rice in that region; and

the Centro Internacional de Agricultura Tropical

in Colombia, which undertakes rice research

relevant to Latin America and the Caribbean (as

well as global research on some other crop


These international research centers are

working on some or all of the critical issues mentioned

in the previous chapter. They do not work

in isolation, but collaborate with one another and

with other, national agencies through research

consortia, different types of networking, and

joint ventures. Rice research issues can be

resolved more easily and in relatively less time

through such collaboration. Working with relevant

partners also has many synergistic benefits:

speeding the transfer of information and advanced

research methodologies, shortening the

time needed to solve problems, enabling scientific

collaboration across political borders and

economic barriers, and stretching scarce research

resources. Similarly, the Food and Agriculture

Organization of the United Nations (FAO) assists

countries in rice sector development by organizing

research, development, and extension activities,

particularly through networking. Descriptions

of the rice-related activities and collabora-

Recent advances in molecular biology have aided rice researchers immensely.

International rice research and development 45

tive mechanisms of the three international research

centers and FAO are given here.

In the following sections, brief descriptions

of the research activities of the three CGIAR

centers involved in international rice research are

given. Progress in and results of their research

are documented in a variety of scientific and

popular publications. Each center generally

produces a corporate annual report, a volume of

research highlights, and a list of publications that

are available from the center on request.

International Rice Research

Institute (IRRI)

Mandate and structure

IRRI’s mandate is to improve the well-being of

present and future generations of rice farmers

and consumers, particularly those with low

incomes, by generating and disseminating ricerelated

knowledge and technology of short- and

long-term environmental, social, and economic

benefit, and to help enhance national rice

research systems.

IRRI was established in 1960 by the Ford

and Rockefeller Foundations with the support of

the Government of the Philippines, and consists

of laboratories and training facilities on a 252-ha

experimental farm in the Philippines. It has more

than 50 international staff there plus outposted

scientists working with national programs in

various countries in Asia.

Research programs

IRRI’s research programs in the past were built

around the different rice-growing ecosystems. In

2000, a new program structure was developed,

based on problem-focused tasks and emerging

issues in the main rice production systems. This

structure allows more efficient allocation of

resources and fast tracking of impact. The new

programs, outlined below, take full advantage of

the advancement of science to address emerging

development concerns and provide stronger

linkage of IRRI’s research with its outreaching

staff and activities as well as with national

research institutions.

Genetic resources conservation,

evaluation, and gene discovery

IRRI’s work on the collection, conservation,

characterization, documentation, and exchange

of germplasm for research on genetic

enhancement and sustaining biodiversity is

housed in this program, which has two elements:

• germplasm conservation, characterization,

documentation, and exchange and

• functional genomics.

The first entails maintenance of IRRI’s

efforts to collect and conserve the genetic

resources of rice, now held in trust in the

International Rice Genebank; and strengthening

of efforts to characterize and evaluate the

conserved germplasm, explore important traits,

and describe allelic diversity using molecular

techniques. The second, on functional genomics,

aims to understand the biological functions

encoded in rice genes, taking advantage of the

investment made in the private sector in

sequencing of the rice genome. IRRI remains

committed to ensuring public access to rice

genetic information. IRRI will develop

additional genetic databases and establish a

bioinformatics system (i.e., integration of data

from DNA sequences, phenotypes, and

functional diversity of rice genes in the

germplasm pool) to assist national institutions in

the discovery of new genes and traits.

Enhancing productivity and sustainability

of favorable environments

The major factor in poverty alleviation in recent

years has been the reduction in the unit cost of

production and the downward trend in real prices

of food. Improved technologies were adopted

fastest in the favorable irrigated environment,

which accounts for nearly 45% of the rice land

and more than 70% of total rice production.

Because of its importance, we must continue to

focus on this favorable environment as the major

source of rice supply to meet the growing

demand from the expanding urban population

and the rural landless. The challenges are how to

sustain the high yields already achieved in this

ecosystem and whether modern science can be

used to explore possibilities of a further shift in

yield potential. The options for extending the

area under high-yielding modern rice varieties by

developing irrigation infrastructure will no

longer be available for many countries because

of the looming water crisis. Farmers need

assistance from rice scientists on how to grow

rice with less water and how to operate irrigation

systems more efficiently. Technological options

must be developed to maintain soil fertility and

control pest pressure.

46 Rice almanac

A consortium of national research centers

throughout Asia and institutions in Australia,

Europe, and North America are active in all the

major irrigated rice countries and will continue

to address important problems of sustainability

and productivity by forming multi-institutional

research partnerships. These partnerships should

result in the development and dissemination of

new technologies for irrigated rice production.

The program has four elements:

• genetic enhancement for yield, grain

quality, and stress resistance;

• managing resources under intensive ricebased


• enhancing water productivity in rice-based

systems; and

the Irrigated Rice Research Consortium.

Improving productivity and livelihood for

fragile environments

The fragile environments—the infertile uplands,

rainfed lowlands subject to frequent droughts

and submergence, and the deepwater and coastal

areas that suffer from flooding, strong winds,

salinity, and other soil-related problems—have

had limited benefits from rice science and

technological developments. The available

modern varieties do not adapt well to these

ecosystems and farmers get low and unstable

yields and limited gains in profits when they

adopt them. As a result, the traditional varieties

are still widely grown and the average rice yield

has remained low at 1.5 to 2.5 t/ha. These

ecosystems, characterized by low farm incomes

and high incidence of poverty, account for about

55% of the rice lands. High-yielding modern

varieties that are tolerant of droughts,

submergence, and problem soils are needed,

along with efficient crop management practices,

to induce farmers to adopt them and to make a

direct assault on poverty.

Recent advances in molecular biology—in

tagging and characterization of genes and their

transfer to other species—have greatly improved

the probability of success in this area. Since the

environments are diverse and their domains vary

across countries, the research must be done in

partnership with national institutions, drawing on

local scientific expertise and farmers’ indigenous


Two consortia of research institutions are in

place to address the problems of increasing and

stabilizing productivity in the rainfed lowlands

and uplands, respectively. In these consortia,

groups of national research centers are working

with IRRI on prioritizing regional research

needs, undertaking interdisciplinary research on

productivity, sustainability, and diversity of ricebased

cropping systems, and exchanging and

evaluating rice germplasm and technology.

The program’s three elements are

• genetic enhancement for improving

productivity and human health in fragile


• natural resource management for rainfed

lowland and upland rice ecosystems, and

• rice research consortia for fragile


Strengthening linkages between research

and development

Demand has been growing for a more interactive

process in research planning, combining topdown

and bottom-up approaches for a better

assessment of the technology needs of farmers,

the priorities of rice research, the probability of

research success in addressing emerging

problems, and feedback on farmers’ criteria for

evaluating scientific knowledge in the context of

their traditional knowledge. Such an approach

may help improve the efficiency of research,

reducing the risk that technologies and scientific

output will remain on the shelf or be used only

for academic purposes.

The new program in this area will incorporate

ongoing socioeconomic research on understanding

rural livelihoods, assessing technology

needs of farmers, and validating technologies

through farmer-participatory experiments in

three projects:

• understanding rural livelihood systems for

research prioritization and impact assessment,

• enhancing ecological sustainability and

improving livelihoods through ecoregional

approaches to integrated natural resource

management, and

• facilitating rice research for impact.

The first deals with research prioritization

and impact assessment based on understanding

farmers’ needs and livelihood strategies, and

interactions among technologies, infrastructure,

and institutions. The second applies ecoregional

approaches at selected sites to demonstrate the

use of systems models for improving rural

livelihoods through efficient management of

International rice research and development 47

Integrated Natural Resource

Management at IRRI

Much of IRRI’s research in the past has been in the

area of integrated natural resource management

(INRM)—albeit under different names. The ultimate

goal of the Institute’s research on the more efficient

use of natural capital such as water and soil is to

protect and improve the environment while maintaining

and improving rice yields.

Long-term yield/productivity. In recent decades,

IRRI and other institutions have been concerned

about the sustainability of intensive irrigated rice

production. Based on IRRI’s own long-term

research, evidence suggested that, under continuously

flooded rice with three crops per year, yields

declined significantly.

However, with help from a 100-strong team of

researchers in China, India, Indonesia, the Philippines,

Thailand, and Vietnam, exhaustive long-term

experiments have shown that, in tropical and

subtropical Asia, yield declines seem to be less

common than previously thought. IRRI’s fields

proved to be one of the exceptional cases, probably

because of prolonged soil wetness at the experiment

station that is less commonly observed in farmers’


Nevertheless, the research also pointed out that

in farmers’ fields there has been a general slowdown

in gains in productivity, a measure of output in

relation to all inputs of rice production. Most studies

have found that productivity growth was healthy in

the 1970s, ’80s, and early ’90s, but it is not possible

to predict future trends. The findings point to the

need for continued research on ways to improve both

rice yield and productivity to ensure that rice production

is profitable for farmers and that rice prices

are low for consumers.

SSNM. Site-specific nutrient management or

SSNM is a tactic that has been successfully tested in

more than 200 on-farm experiments across Asia. The

generic approach is to make fertilizer applications

more efficient. By using a leaf color chart and a

fertilizer calculation chart, farmers can assess

whether and how much fertilizer is needed at any

time during the growth of the rice plant. Average

yields and profits have shown increases of 10–15%.

Pilot studies at the village level began in six Asian

countries in 2001. The leaf color chart, in particular,

has proven to be an inexpensive guide to nitrogen

fertilizer status and is catching on across Asia.

Land leveling. Proper leveling of farmers’

fields has potential for a major impact on rice

production in South and Southeast Asia. After

flooding, level fields drain much faster than

unleveled fields, reducing weed incidence and

improving the timeliness of land preparation and

crop establishment. Tests have shown that leveling

improves yields by 15% without fertilizer and up to

28% with recommended fertilizer use. Leveling also

provides a 40% reduction in weed biomass, a 5–7%

increase in crop area by removal of bunds, a 10%

reduction in water requirements, and an increased

opportunity for direct seeding, which dramatically

cuts labor needs.

Ongoing regional-level INRM research.

Together with other centers within the Consultative

Group on International Agricultural Research, other

advanced research institutes, nongovernmental

organizations, and national research institutions, IRRI

is involved in two initiatives that span different

ecological zones:

• Ecoregional Initiative for the Asian Humid and

Subhumid Tropics—using a systems approach

to develop research and operational methods

of INRM that can be used at the regional level.

The research uses a bottom-up approach, that

is, focusing on the implications and

cumulative effects of field and farm

interventions at higher geographical levels of

integration. A top-down approach is also used

in tackling resource-use issues.

Rice-Wheat Consortium for the Indo-Gangetic

Plains—in a region (South Asia) of increasing

demand for food grains, where past sources of

productivity increases (e.g., modern varieties,

fertilizers, irrigation investment) have been

exhausted, and where soils are being degraded

and groundwater depleted, to improve yields

through integrated crop, soil, and residue

management. A holistic approach is being

taken to combine resource conservation

approaches for rice with promising wheat

production technologies that use reduced or

zero tillage.

New INRM research. IRRI’s new projects on

integrated natural resource management, outlined in

the Institute’s latest medium-term plan, became

operational in January 2001. As with the INRM

research results described above, with the exception

of the region-level work, the new studies, listed

below, are based at the field and farm level. They are

components of one or more of the four IRRI research

programs described in this section:

• Natural resource management for the rainfed

and upland ecosystems

• Managing resources under intensified ricebased


• Enhancing water productivity in rice-based


• Understanding rural livelihood systems for

research prioritization and impact assessment

• Ecoregional approaches to integrated resource

management and livelihood improvement.

48 Rice almanac

natural resources. The third aims at

understanding the pathways of technology

dissemination, and validation and adaptation of

promising technologies through farmerparticipatory

research to be conducted in

partnership with nongovernmental organizations,

the private sector, and other extension agencies.

International collaborative research

mechanisms at IRRI

IRRI is involved in a variety of international

partnerships: research consortia, research

networks, technology evaluation networks, joint

ventures, shuttle research, bilateral collaboration,

and direct consultation.

Research consortia

A consortium is defined here as a group of a

limited number of national and international

institutions formally organized to collaborate in

research, training, and technology-generating

activities designed to meet mutually agreed

objectives. Three ecosystem-based consortia

involving IRRI are currently active:

Rainfed Lowland Rice Research Consortium

The national research systems in Bangladesh,

India, Indonesia, the Philippines, and Thailand,

and IRRI are conducting targeted research at

seven key sites that represent different rice

production constraints in subecosystems of the

rainfed lowlands: drought-prone, submergenceprone,

drought- and submergence-prone, and

medium-deep water.

Upland Rice Research Consortium

The national research systems in India,

Indonesia, the Philippines, and Thailand, and

IRRI have targeted five key sites, each of which

represents a subecosystem and a major

production constraint. Research is under way on

the impact of drought, problem soils, weeds, land

degradation, and blast disease on rice

productivity, environmental security, and the

well-being of upland farm families. Improving

rice productivity is seen as the entry point to

alleviating interrelated problems that contribute

to upland degradation and damage to the lowland


Irrigated Rice Research Consortium

This group, composed of national research

institutions from China, India, Indonesia, Lao

PDR, Malaysia, the Philippines, Thailand, and

Vietnam, is working with IRRI to create regionwide

multidisciplinary and integrated research

projects to look at the interaction of crop

production with the resource base, natural

arthropods, pathogens, and weed communities,

and the assessment of the effects of these

interactions at local, regional, and global scales.

Research networks

Individual scientists from IRRI and other

institutions organize and conduct research driven

by a particular theme or set of research tools.

Two networks are currently convened by IRRI:

• Asian Rice Biotechnology Network

(ARBN), established at IRRI in 1993 to

provide a vehicle for collaborative research

in rice biotechnology with universities and

rice breeding institutes of the Asian

countries. ARBN, through its training and

collaborative research activities, is

providing a unique mechanism for national

research institutions to gain access to

relevant knowledge and biotechnology

tools. The ultimate goal is to assist them in

applying biotechnology to meet their own

national needs in rice varietal


• Hybrid Rice Network, which aims to speed

up development and use of hybrid rice

technology in Asia. Current activities are

in Bangladesh, India, Indonesia, the

Philippines, Sri Lanka, and Vietnam, in

collaboration with FAO, the Asia Pacific

Seed Association, and China. The network

has contributed significantly to the

development and promotion of hybrid rice


Technology evaluation networks

These voluntary, open, informal associations of

scientists and research organizations enable

members to exchange and evaluate technologies

systematically and share experiences and

information. Two are coordinated at IRRI:

The International Network for the Genetic

Evaluation of Rice (INGER), created to evaluate

promising cultivars, elite breeding lines,

traditional cultivars, and genetic donors through

a network of multilocational trials in different

environments and subject to different stresses.

Crop and Resource Management Network

(CREMNET). The objective of this network is to

International rice research and development 49

evaluate prototype technologies for sustainable

production systems in different agroecological

and socioeconomic situations.

Other mechanisms

As partners in national systems of rice-growing

countries undertake more and more of the needed

strategic and applied research, IRRI is shifting its

agenda to conduct more anticipatory research in

new partnerships. These include

• shuttle research in which IRRI and another

institution exchange scientists to undertake

specific phases of a project, for example,

the IRRI-Japan Shuttle Project, which

focuses on biotechnology, pathosystems,

physiology of rice and yield, microbiology,

and social science, maximizes the use of

scientific research in Japan, and gives

Japanese scientists exposure to tropical


• bilateral collaboration with stronger

national institutions in which IRRI and

collaborating institutions agree on a joint

work plan for specific activities of mutual

benefit; bilateral work plan meetings

between IRRI and such national

institutions are held biennially for this

purpose; and

• special projects to strengthen less

developed national institutions, in which

IRRI provides support in four major

themes—rice research strategy and

associated work plans, productivity and

quality of research implementation,

national research linkages to extension and

farmers, and international linkages among

national and international research


West Africa Rice Development

Association (WARDA)

Mandate and structure

WARDA is an autonomous intergovernmental

research association of 17 countries in West and

Central Africa: Benin, Burkina Faso, Cameroon,

Chad, Côte d’Ivoire, The Gambia, Ghana,

Guinea, Guinea Bissau, Liberia, Mali,

Mauritania, Niger, Nigeria, Senegal, Sierra

Leone, and Togo. WARDA was founded in 1970.

Since 1986, WARDA has also been a member of

the CGIAR. WARDA’s mission is “to contribute

to food security and poverty alleviation in poor

rural and urban populations, particularly in West

and Central Africa, through research, partnerships,

capacity strengthening, and policy support

on rice-based systems, and in ways that promote

sustainable agricultural development based on

environmentally sound management of natural


Rice is a unique and highly political commodity

in Africa. Because of its ease of preparation,

low preparation costs, low price, and steady

supplies (through imports), rice consumption is

increasing rapidly, providing food security for

Africa’s poor. Because of its large genetic diversity,

it tolerates extreme soil and weather

conditions, allowing farmers to produce food in

adverse environments. Rice is also an integrating

crop. Rice development often acts as an entry

point for the development of the agricultural sector

as a whole by enhancing household food security,

reducing production risk, enhancing income,

and averting natural resource degradation.

WARDA will therefore seek to contribute to poverty

alleviation in Sub-Saharan Africa through

integrated sustainable development of the rice

sector, particularly through technology development.

WARDA’s ultimate beneficiaries are rice

producers and consumers in West and Central

Africa. WARDA’s more immediate beneficiaries

are its research and development collaborators,

such as national agricultural research and extension

systems and nongovernmental organizations


Research areas and strategy

Africa’s land resources are typically poor and

fragile. In the rainfed uplands, shortened fallow

periods and slash-and-burn agriculture lead to a

general decline in land quality through erosion

and soil-fertility mining. The increase in population

pressure, limited capital, poor market access,

and labor shortage aggravate the situation,

resulting in low and unstable rice yields. In the

rainfed lowlands, poor water control and

infestation by weeds, pests, and diseases (e.g.,

blast, rice yellow mottle virus, African rice gall

midge) are major constraints, in addition to

population pressure, limited capital and

investment, land-tenure issues, and lack of

mechanization. In the irrigated systems, the main

constraints are related to input access, limited

mechanization, and knowledge on best-bet crop

and natural resource management practices.

WARDA’s research focuses on three main rice

50 Rice almanac

ecologies (upland, rainfed lowland, and irrigated

rice) and provides support to national research in

the mangrove and deepwater ecosystems.

WARDA’s research strategy first builds on

past achievements, such as WARDA’s New Rice

for Africa (NERICAs), based on crosses between

African rice (Oryza glaberrima) and Asian rice

(O. sativa). Other important achievements include

the use of participatory varietal selection (PVS)

methods, the development of community-based

seed supply systems, the introduction of highyielding

rice cultivars combined with integrated

crop management practices in irrigated Sahelian

systems, and improved understanding of soil

degradation processes (salinization, alkalinization)

under irrigation in the Sahel.

WARDA’s research strategy is ecologybased

and can be summarized as follows: (1)

stabilization of the rainfed upland systems, (2)

intensification and diversification of rainfed lowland

systems, and (3) improvement of resourceuse

efficiency in irrigated rice systems.

Rainfed upland environment

Given the need to stabilize the rainfed upland

environment and the success of the NERICAs,

WARDA implements its research strategy for

this environment along the following four lines:

• Increased use of NERICA seed in farmers’

fields. PVS work in Guinea and Côte

d’Ivoire has shown the potential of

NERICAs in farmers’ fields. In the coming

decade, WARDA will expand the number

of farmers exposed to NERICAs

throughout the region through PVS.

• The development of new inter- and

intraspecific rice cultivars. WARDA will

enlarge the gene pool for uplands using

advanced and more traditional breeding

tools. In addition, participatory plant

breeding will provide farmer input into

WARDA’s breeding program and speed up

the identification of favorable plant

material with resistance to drought and soil


• Validation and dissemination of integrated

natural resource management (INRM)

practices. INRM practices ensure

preservation of the natural resource base

and/or sustainable intensification. Building

on previous achievements in the

development of N-fixing fallow legumes

and the introduction of a modest use of

fertilizer, including rock-phosphate,

emphasis will be placed on integrated biophysical

and socioeconomic assessment of

these technologies and the formulation of

adequate baskets of technologies.

• Creating an enabling environment for the

scaling-up of NERICAs and INRM

practices. For the varietal component, a

focus will be placed on community-based

seed supply systems to address weak seed

multiplication systems for farmers of

rainfed rice. For INRM, the focus will be

on strengthening the capabilities of rice

development stakeholders in applying research


Rainfed lowland environment

Given the need to intensify and diversify the

rainfed lowland environment and the success of

the NERICAs in rainfed upland environments,

WARDA is undertaking the following research:

• Develop new germplasm for lowland

conditions. Evaluation of inter- and

intraspecific crosses for lowland

conditions is being expanded to obtain a

range of appropriate plant material. This

includes screening of available NERICAs

and application of PVS. Particularly

promising is the recent identification of a

gene for resistance to rice yellow mottle

virus, which will result in widespread

availability of rice cultivars resistant to this

virus in the coming decade.

• Identify INRM practices. Water management

is the key factor for increased

productivity and a means of controlling

iron toxicity in the lowlands. WARDA

assesses feasible modes of water

management with respect to the

biophysical environment, and farmers’

means and perceptions.

• Develop options for diversification. Given

the potential of vegetables to diversify

rice-based lowland systems, WARDA has

started to mobilize resources to address

integrated rice-vegetable cropping in

rainfed lowlands, such as the inland-valley

bottoms. Other options that need to be explored

include integration of aquaculture

and livestock.

Inland valleys offer the greatest potential for

expansion, intensification, and diversification in

Sub-Saharan Africa. Inland valleys are the upper

International rice research and development 51

eaches of river systems, in which alluvial

sedimentation processes are absent or of little

importance. They are located upstream from

river floodplains that are much wider. Inland

valleys address the whole toposequence, or

continuum, including valley bottoms, which may

be submerged for part of the year, their

hydromorphic fringes, and the contiguous upland

slopes and crests extending over the area that

contribute runoff and seepage to the valley


Inland valleys have a key role to play in

providing options for sustainable intensification

and diversification of agricultural production in

Sub-Saharan Africa. Soils in lowland ecosystems

are the least fragile and best able to support

continuous cultivation. The soils in many valley

bottoms retain residual moisture well after an

initial flooded rice crop, permitting two crops per

year, or aquaculture when base flow lasts long

enough. The hydromorphic fringes and upland

slopes and crests offer potential for other food

and cash crops, and for trees and livestock. Thus,

inland valleys constitute an important

agricultural and hydrological asset at the local

and national level, and can make a major

contribution to future food security and poverty

alleviation in Sub-Saharan Africa.

Inland valleys cover approximately 200

million hectares in Sub-Saharan Africa. Only a

small fraction, probably less than 15%, is

currently used in the subhumid and humid zones

and crop yields are low, for example, rice yields

are around 1 t/ha. There is tremendous potential

for intensified and diversified use of inland

valleys. Productivity can be improved

substantially by improving water control,

agronomic or breeding innovations, growing

crops other than rice or crops after rice (such as

vegetables or legumes), introducing aquaculture,

and/or introducing low-cost water harvesting and

management systems. Next to their agricultural

potential, inland valleys have other important

social and ecological service functions, such as

water storage and/or drainage, and maintenance

of biodiversity.

Inland valleys have very complex, dynamic,

and diverse human, social, natural, and physical

dimensions and interconnections. This

complexity needs to be understood to determine

options for improved and integrated natural

resource management. Given the diversity of

inland-valley ecosystems, a bottom-up social

learning process will be critical. Only then can

sustainable and lasting impact on food security in

the region be achieved. A participatory learning

and action research approach among inlandvalley

development stakeholders (farmers,

change agents, extension, research) at the grassroots

level is required. This will help build

bridges between indigenous knowledge and

scientific expertise, and stimulate the formation

of networks between farmers and other inlandvalley

development stakeholders. It will also be

instrumental to the development of an INRM

framework and curriculum for farmer learning

for inland valleys in West Africa. WARDA is

using integrated rice management as an entry

point to INRM for inland valleys. A complete

curriculum has been developed, containing a

facilitators’ manual and a technical manual

dealing with all management interventions from

land preparation to harvest and postharvest

issues. The Inland Valley Consortium (10 West

and Central African countries hosted by WARDA

that focus on intensified but sustainable use of

inland valleys) forms the foundation of the

inland-valley research and development platform

that is being built at regional and national levels.

Irrigated lowland environment

Given the need to improve the resource-use

efficiency in irrigated lowland environments and

the success of the Sahel cultivars and integrated

crop management (ICM), WARDA implements

its research strategy for this environment along

the following three lines:

• Breeding. In the irrigated lowland

environments, breeding uses the enlarged

gene pool provided by inter- and

intraspecific cultivars. Breeding activities

focus on developing high-yielding shortduration

cultivars with good grain quality

and resistance to major African stresses.

Emphasis is being placed on developing

varieties that are competitive with weeds

in direct-seeded systems.

• Further development and extrapolation of

ICM practices. ICM decision-support systems

developed for the Sahel are being

evaluated and disseminated to other areas,

in particular to irrigation schemes in northern

Nigeria. ICM is being adapted for the

medium-input irrigation systems in the

52 Rice almanac

(sub-)humid agroecological zones.

Potential spillover to the low- to mediuminput

rainfed lowland systems is given

particular attention.

• Identification of INRM practices. To

ensure the success of ICM, sound natural

resource management practices need to be

developed. Particular attention is paid to

soil and water management at the farm and

water-basin levels and preservation of the

natural resource base, that is, maintenance

of soil fertility and avoidance of salinity

buildup. Senegal is used as a pilot case,

taking advantage of the knowledge accumulated

on irrigated systems.

Constraints that cut across ecosystems include

the generally unstable socioeconomic environment,

dysfunctional information and communication

systems, poor research and development

(R&D) linkages, and limited market integration.

To respond to these challenges, WARDA considers

development of new partnerships of great

importance, including alliances with

nontraditional stakeholders such as NGOs, the

private sector, and farmers’ organizations. Enhanced

collaboration through participatory approaches

will improve research priority setting

and enhance the effectiveness and efficiency of

R&D efforts. WARDA attaches great importance

to developing labor-saving technologies and ricebased

production systems that provide additional

nutritional value that could mitigate the effect of

HIV/AIDS on the welfare of the rural population.

To ensure the relevance of technologies and

to facilitate scaling-up, end-users (such as

farmers and extension agents) are involved

throughout the technology development and

dissemination process. Technologies need to be

easy to implement by women (because many rice

farmers are women). WARDA ensures that

research is conducted with a holistic view, that

is, the combined effect of a technology on productivity,

farmer well-being, and the quality of

the natural resource base will be assessed.

Implementing WARDA’s research


Implementing WARDA’s research strategy

comprises four essential elements:

• Technology generation for sustainable


• Technology dissemination and farmer


• Policy research

• Capacity building and training of key

agents of change

WARDA’s rainfed and irrigated area

programs result in improved technologies for the

respective environments. These programs

address technology generation and dissemination,

from upstream strategic research targeting

specific constraints to the application and

integration of different technology components

in farmers’ fields. WARDA’s Rice Policy and

Development Program addresses the overall

environment in which the proposed technology

will be disseminated and used, from the farm

level up, including higher aggregation levels

such as watersheds, markets, agroecological

zones, nations, and regions. This program

thereby focuses on problems that cut across

ecosystems, particularly with respect to policy

research and scaling-up technology

dissemination. The fourth principal element,

capacity building and training, is not specifically

linked to any particular program. Instead, it is

integrated into each program under the

coordination of a training unit.

The boundary between the two ecologybased

programs is not rigid. First is the uplandlowland

continuum in rainfed environments.

Second is the anticipated intensification of

rainfed lowland rice farming and the corresponding

investment in water management, creating a

continuum from purely rainfed to fully irrigated

lowland. Third, there has been a shift since the

late 1990s in the irrigated rice program from the

Sahel toward the (sub-)humid zones. Consequently,

strong synergies exist between the two

ecology-based programs.

International collaborative research

mechanisms at WARDA

The rice-producing environments of West and

Central Africa are too varied, the production

constraints too many and complex, and

WARDA’s resources too small for the association

to have significant impact working alone.

WARDA requires the contributions of scientists

in national programs, in other CGIAR centers,

and from advanced research institutions in

developed countries. To ensure efficiency and to

avoid duplication, these diverse resources need

International rice research and development 53

to be combined in a coherent and complementary

regional research program.

It is with this objective that WARDA has

developed the character of an “open center.” This

means that WARDA provides a permanent

institutional framework within which to attract,

focus, and facilitate the efforts of a range of

collaborators. The unifying factor is that all

partners contribute to solving priority regional

problems. While WARDA generally serves as a

catalyst to identify the priority themes and

partners for collaborative research, research

leadership in any given area is determined on the

basis of institutional comparative advantage.

Partnership with national agricultural

research and extension systems (NARES)

The goal of WARDA’s partnership with national

systems is to achieve the most cost-effective

means of developing and transferring new rice

technologies within the region as a whole.

WARDA views the regional rice science

infrastructure as an integrated and interdependent

system. Because agroecological environments

cut across political boundaries, technologies

developed in any single location are usually

transferable to far broader areas. The objectives

of WARDA’s partnership with NARES are to

achieve a more complementary and efficient

sharing of research tasks by allocating responsibilities

on the basis of comparative advantage,

and to maximize research spillover between

these systems and WARDA, and among the national

systems themselves.

The Reseau Ouest et Centre Africain du Riz

(ROCARIZ), a Rice Research and Development

Network for West and Central Africa, was created

in 2000 after in-depth consultations among

WARDA, the West and Central African Council

for Agricultural Research and Development

(WECARD/CORAF), national research systems,

and the U.S. Agency for International Development

(USAID). ROCARIZ is a successor network

to the highly successful WARDA/NARS

Rice Task Force Collaborative Mechanism for

rice research and development within the

subregion, which was supported financially by

USAID in 1991-97. ROCARIZ maintains the

task force structure with seven functional task

forces on mangrove swamps, rice breeding,

Sahel resource management, integrated pest

management, natural resource management, rice

economics, and technology transfer. ROCARIZ

finances small two-year research projects

through national scientists in member countries.

The technology transfer task force includes the

active participation of researchers, extension officers,

and end-users of research results.

ROCARIZ has established a forum—the Biennial

Regional Rice Research Review (4Rs)—for

reporting and publishing rice research and development

activities within the subregion. The principal

stakeholders of ROCARIZ are WARDA,

CORAF member countries, national research

systems, USAID, the private sector, and rice

farmers. ROCARIZ values its guiding principles

of trust, mutual respect, and joint ownership—

essential ingredients for a successful partnership

program. ROCARIZ is coordinated at WARDA

headquarters and is managed by a coordinator

under the guidance of a steering committee composed

of national scientists, the private sector,

development agents, and a WARDA representative.

WARDA’s genetic resources unit comprises

traditional genebank operations, but also the

International Network for Genetic Evaluation of

Rice in Africa (INGER-Africa). The genebank

activities have taken up a higher profile with the

successful use of the Oryza glaberrima rice species

in the development of NERICAs. Oryza

glaberrima and wild African species are priority

areas for collection, conservation, and

characterization. During the 1990s, INGER-Africa

became a demand-responsive network providing

new genetic material for NARES partners,

including nominations from the NARES

themselves (effectively allowing such material to

undergo regional adaptation testing). INGER-

Africa has also embarked upon studies of

biodiversity (variety portfolio) management by

farming communities.

In addition to traditional national partners,

WARDA has recently been expanding its partnership

mode to encompass the NGO community,

the private sector, regional universities, and

farmers’ organizations. In particular, a community-based

seed system has been promoted in

Côte d’Ivoire and Guinea in collaboration with

NARES, NGOs, private seed companies, and

farmers’ organizations.

Partnership with advanced research


Many institutions in the global research

community have strengths in specialized areas

that are highly complementary to WARDA and

54 Rice almanac

national programs. WARDA proactively identifies

and mobilizes these potential partners

through collaborative research projects that focus

on priority problems. In some instances, research

is conducted within the partner institution. Alternatively,

partner institutions outpost a collaborating

scientist to WARDA, where she/he becomes

a full member of WARDA project teams.

WARDA is currently collaborating with the

following partner institutions: IRRI (Philippines),

Centro Internacional de Agricultura

Tropical (CIAT, Colombia), Asian Vegetable Research

and Development Center (AVRDC,

Taiwan, China), Centro Internacional de

Mejoramiento de Maíz y Trigo (CIMMYT,

Mexico), Food and Agriculture Organization of

the United Nations (FAO, Italy), International

Crops Research Institute for the Semi-Arid

Tropics (ICRISAT, India), International Food

Policy Research Institute (IFPRI, USA),

International Institute of Tropical Agriculture

(IITA, Nigeria), International Livestock Research

Institute (ILRI, Ethiopia and Kenya), International

Water Management Institute (IWMI, Sri

Lanka), Aberdeen University (UK), Cemagref

(France), Centre de coopération internationale en

recherche agronomique pour le développement

(CIRAD, France), CABI Bioscience (UK),

Cornell University (USA), Danish Government

Institute for Seed Pathology (Denmark), Horticultural

Research International (UK), Institut de

recherche pour le développement (IRD, formerly

ORSTOM, France), International Centre for Insect

Physiology and Ecology (ICIPE, Kenya),

International Laboratory for Tropical Agricultural

Biotechnology (ILTAB, USA), Japan International

Cooperation Agency (JICA), Japan International

Research Center for Agricultural Sciences

(JIRCAS), John Innes Centre (UK), Laval

University (Canada), Leeds University (UK),

Natural Resources Institute (UK), Sainsbury

Laboratories (UK), University of Hohenheim

(Germany), University of Louvain (Belgium),

University of Tokyo (Japan), Wageningen

University and Research Centre (WUR, The

Netherlands), and Yunnan Academy of

Agricultural Sciences (YAAS, China).

Inland Valley Consortium

WARDA hosts a research consortium of 10

countries (Benin, Burkina Faso, Cameroon, Côte

d’Ivoire, Ghana, Guinea, Mali, Nigeria, Sierra

Leone, and Togo) and international research


IITA, ILRI, IWMI, WUR). The consortium aims

to enhance cooperation and complementarity

among R&D institutions working with the

common goal of intensifying the cultivation of

inland valleys in a sustainable and environmentfriendly

manner. Consortium members work

together to characterize driving forces,

constraints, and technical needs for inland-valley

development, to develop improved low-cost

water management systems, to test component

agronomic technologies, and to assess their

socioeconomic and environmental impact. Each

of these activities is conducted at key sites

selected as being representative of broader

domains in West and Central Africa.

NERICA Consortium for Food Security in

Sub-Saharan Africa

The consortium to expand and speed up the

dissemination and adoption of the “New Rice for

Africa” and complementary technologies was

launched at an international workshop in March

2002. Broad participation is expected,

encompassing NARES; donors, including the

United Nations Development Programme; Japan;

World Bank; African Development Bank;

Rockefeller Foundation; USAID; NGOs,

including Sasakawa Global 2000, Organisation

des Volontaires pour le Développement Local

(OVDL), Association d’Appui et d’Aide aux

Groupements Ruraux (Mali); farmers’

organizations; and the private sector, including

Pioneer Seed (Nigeria). The consortium will not

only evaluate the available technology and help

develop new technologies but will also identify

constraints to effective adoption and scaling-up.

It will also provide a mechanism for introducing

participatory varietal selection and communitybased

seed systems to East and southern Africa.

Centro Internacional de

Agricultura Tropical (CIAT)

(International Center for Tropical


Mandate and structure

CIAT seeks to contribute to the alleviation of

hunger and poverty in tropical developing

countries by applying science to the generation

of technology that will lead to lasting increases

in agricultural output while preserving the

International rice research and development 55

natural resource base. To fulfill this mission,

CIAT scientists integrate two lines of


• Commodities. The Center has a long and

successful history of research on

commodities for which its mandate is

global (beans, cassava, and tropical

forages) or regional (rice in Latin America).

• Agroecosystems. Through initiatives in the

forest margins, hillsides, and savannas of

tropical America, CIAT applies a wide

range of expertise to research on the

management of natural resources.

The Rockefeller and Ford Foundations

established CIAT in 1967 with support from the

Government of Colombia. The Center’s 500-ha

headquarters is near Palmira in the Cauca Valley

of Colombia. CIAT has 70 international staff

members from 30 countries, working with

national agricultural research programs in Latin

America, the Caribbean, Africa, and Asia.

Rice project

The rice project’s goals have been extended since

its creation in 1967, from improving the

nutritional and economic well-being of rice

growers and low-income consumers in Latin

America and the Caribbean to include the

development of sustainable increases in rice

production and productivity. The CIAT rice team

has eight internationally recruited staff and

approximately 40 national staff. This

multidisciplinary team works to make rice an

economically viable crop that contributes to food

security and acts as a vehicle to reduce poverty.

The objective is to help resource-poor rice

farmers, with the knowledge that the benefits

extend to the entire rice-farming community.

The past three decades of collaboration

among IRRI, CIAT, Centre de coopération

internationale en recherche agronomique pour le

développement, and national rice improvement

programs have resulted in high-yielding rice

varieties in farmers’ fields, networks of

germplasm improvement, and sharing of

information. Evaluation of the new plant types

developed at IRRI to increase rice yields is under

way as well as the identification and use of new

genes from wild germplasm to increase yield

potential and broaden the genetic base of

cultivated rice.

CIAT’s rice research program aims to make

significant contributions to environmental goals

such as protecting soil and water and reducing

agrochemical use by devoting its efforts to

developing improved rice varieties and

integrated crop management. The program also

collaborates in developing rice as a component

of cropping systems for the savannas and

lowland rainfed tropics. Breeding to develop

germplasm adapted to the acid-soil savannas and

the understanding of rice/pasture/other crop

associations will lead to more sustainable rice

production in this ecosystem and a more rational

use of pesticides.

CIAT’s rice project works closely with the

Center’s national partners to solve problems and

receives support from several national programs

in the region. CIAT is a member of the Fund for

Latin American Irrigated Rice (Fondo

Latinoamericano de Arroz de Riego or FLAR),

which is mainly supported by the public and

private sector. Close collaboration with national

partners and FLAR ensures continuity in rice

research activities at the regional level. This

process clearly shows that Latin American rice

producers are aware of the value of new


The present program has three research

elements: improved rice gene pools, integrated

crop management, and enhancing regional rice

research capacity.

Improved rice gene pools

The objective of this work is to increase rice

genetic diversity and enhance gene pools for

higher and more stable yields. This research has

five steps:

1. Improved germplasm, which involves

identifying progenitors for crossing,

evaluating segregating material, and

carrying out yield trials.

2. Improved populations (recurrent

selection), requiring evaluation/

recombination of gene pools,

development of blast resistance through

recurrent selection, development of

indica gene pools with a higher response

to anther culture, enhanced pest and

disease resistance, high yield potential,

and excellent quality.

3. Identification and use of genes from wild

germplasm. First, useful wild germplasm

and its traits are identified, followed by

56 Rice almanac

interspecific crosses and the development

of backcross populations. These

populations undergo quantitative trait

loci analysis and suitable isogenic lines

are produced for release as advanced

lines. Anther culture is used to speed up

the process.

4. Determination of the physiological basis

for yield enhancement and adaptation to

abiotic stresses. These traits are

characterized from wild rice and nutrient

uptake is investigated under low pH and

high Al conditions.

5. Developing marker-aided selection, part

of a long-term strategy to give rice

breeders another tool, allowing them to

incorporate even more traits into

enhanced gene pools.

Integrated crop management

The objective of this research is to develop

methodologies to decrease unit rice production

costs and environmental contamination.

1. For rice blast, the research focuses on

characterizing the pathogen and on

disease resistance, involving monitoring

genetic diversity of the blast pathogen,

testing breeding methods for improving

blast resistance, dissecting blastresistance

genes in highly resistant

cultivars, and using recurrent selection

for blast resistance.

2. For the rice sheath blight pathogen, the

research is on characterizing the

pathogen and developing methods for

screening for resistance. A transgenic

approach to control the pathogen is also

being investigated.

3. Rice lines with diversified resistance to

Tagosodes and to rice hoja blanca virus

(RHBV) are being developed in

collaboration with other CIAT projects

and national program breeders, who

evaluate rice germplasm for resistance.

Control of RHBV is attempted using

transgenic resistance strategies.

4. For the rice stripe necrotic virus

(RSNV), research involves studying its

transmission using the vector Polymyxa

graminis, developing control strategies,

and breeding for resistance to the virus.

5. Weed control is being investigated by

identifying traits for competitiveness

and their heredity and seeking

genotypes that emerge under weedsuppressing


Enhancing regional research capacity

The objective of this research is to assure that the

needs of rice farmers are met. This is done

through training and working in a participatory

manner with farmers and our partners to develop

technologies that overcome specific constraints.

1. Participatory development of rice

varieties for the resource-poor farmers.

This involves rice gardens from which

farmers can select the varieties best

adapted to their needs. Also, resourcepoor

farmers participate in selecting

advanced lines from gene pools that

target the limitations that these farmers


2. The CIAT rice project works with

FLAR and national programs to solve

specific regional constraints.

3. Together with its partners, CIAT

develops and makes available training

materials and information.

International collaborative research

mechanisms at CIAT

CIAT is strengthening private and public

linkages and networking in the region’s rice

sector. To this end, the Center takes part, together

with IRRI, in the Caribbean Rice Industry

Development Network (CRIDNet) and in 1995

launched the Fund for Latin American Irrigated

Rice (FLAR) with producer associations from

Brazil, Colombia, and Venezuela. CIAT

continues to be very active in training local

scientists, particularly in germplasm-related and

integrated pest management topics.

FLAR was created as a mechanism to

mobilize public and private resources to maintain

the momentum of irrigated rice research in the

region. Currently, its members are CIAT and

representatives from 10 countries: Argentina,

Bolivia, Brazil, Colombia, Costa Rica, Cuba,

Guatemala, Panama, Uruguay, and Venezuela.

Other countries and international agencies are

encouraged to join the group. FLAR’s resources

come from fees paid by producers, millers, and/

or seed producers’ associations. The fee is based

on each country’s annual rice production.

The research domain of FLAR is germplasm

enhancement and crop management. FLAR’s

International rice research and development 57

objectives are to focus rice-sector activities in an

integrated manner, provide a permanent forum

for the exchange of useful up-to-date

information, share results among the partners,

and strengthen the rice sector in its member

countries by consolidating local and regional

institutional arrangements. Participation of all

actors in the rice sector is encouraged, including

public-sector institutions, universities, and

NGOs. FLAR plays an important role in

diagnoses of national rice sectors, participates in

the elaboration of national rice research plans,

trains scientists to assess priorities, and promotes

the integration of rice producers’ associations

and other nongovernmental associations.


The principal involvement of FAO in rice

research and development is through the

International Rice Commission, established in

1948. Its purpose is to promote national and

international action in matters relating to the

production, conservation, distribution, and

consumption of rice. The members are FAO

member countries in which rice is grown.

The Commission’s functions also include

undertaking cooperative projects directed at

solving rice production problems. The

Commission has an information role in the

production of information on rice matters, and an

advisory role in recommending to the members

actions that appear necessary to solve these


The notable growth in rice production over

the past 50 years is attributable, at least in part,

to the work of the Commission, either directly or

indirectly, in applying technology, implementing

cooperative programs, and disseminating


In the past decade, it has been involved in

setting up several regional networks and working

groups. The Commission’s Secretariat currently


the Inter-Regional Cooperative Research

Network on Rice in the Mediterranean

Climate Areas (Med-Rice),

the Wetland Development and

Management Network/Inland Valley


the Working Group on Hybrid Rice in

Latin America, and

the International Task Force for Hybrid


FAO has a memorandum of understanding

with two international rice research centers: with

IRRI to strengthen collaborative action aimed at

promoting wider adoption of hybrid rice

technology outside China (an agreement that was

extended to include the provision of information

to and joint publication of this Almanac) and

with WARDA to support rapid rice technology

diffusion in West Africa.

During the 1990s, member countries of the

Commission and international institutions

including FAO itself approved and funded nine

technical cooperation projects in support of the

Commission’s work. The Commission’s major

recommendations are implemented by the Rice

Development Programme in collaboration with

national and international institutions and

agencies. This program includes the following


• hybrid rice development and use,

• rice integrated crop management,

• inland-valley swamp development and


• New Rice for Africa (NERICAs),

• prospering with rice, and

• support to the Special Programme on

Food Security.

58 Rice almanac




Rice around the world


World rice production in 2000 was about 600

million t. At least 114 countries grow rice and

more than 50 have an annual production of

100,000 t or more. Asian farmers produce about

90% of the total, with two countries, China and

India, growing more than half the total crop.

For most rice-producing countries where

annual production exceeds 1 million t, rice is the

staple food. In Bangladesh, Cambodia,

Indonesia, Lao PDR, Myanmar, Thailand, and

Vietnam, rice provides 50–80% of the total

calories consumed. Notable exceptions are

Egypt, Nigeria, and Pakistan, where rice

contributes only 5–10% of per capita daily

caloric intake.

The typical Asian farmer plants rice

primarily to meet family needs. Nevertheless,

nearly half the crop goes to market; most of that

is sold locally. Only 6–7% of world rice

production is traded internationally. The major

rice exporters are Thailand, the United States,

Vietnam, Pakistan, India, and China.

In the narratives that follow, we first present

aspects of rice production in Asia, Europe and

the Mediterranean, North America, Latin

America and the Carribean, and West Africa.

Next are shown the rice situation and

outlook for the 10 major rice-producing

countries, followed by tables and graphs of

relevant data on another 54 countries that

produce significant quantities of rice.

In general, the scales of the various graphs

are identical from one country to another for any

given data type (e.g., role of rice in the diet, level

of per capita production). This consistency

allows easier visual comparison across countries,

but it comes at the cost of obscuring the time

trends for countries whose data cluster at the

bottom of the uniform scales.

There are exceptions to this scale consistency,

however. They are most common in the

graphs showing indices of production, area, and

yield because some countries expanded production

and area harvested very rapidly in percentage

terms (often from a very low base) during

the past 35 years. Given such extraordinary rapid

growth, the use of a common scale for all

countries would nearly obliterate the time trends

of many countries, including most if not all of

the world’s major rice producers. Thus, a

decision was made to use different scales for

certain countries on some graphs. When the scale

is not identical across all countries, a note to that

effect is included for the countries with different

scales. In addition to different scales for indices

of production, area harvested, and yield per

hectare, several countries also have different

scales for per capita production (Cambodia,

Guyana, Suriname).

Net trade status is defined here as net

exports (i.e., exports minus imports) divided by

the sum of production plus imports. For these

graphs, the scale is between –100 and +100. This

Rice around the world 59

Drying rice in southern Vietnam.

scale is adequate to cover most instances, but

not all. For some countries (Uruguay and

Australia) in some years, FAO data show that

exports exceeded total production. This is

possible if some of the exports in a given year

came from the previous year’s production.

The source of raw data for all graphs is the

FAOSTAT online electronic database, and the

most recent data for any given category are

preliminary. All indices for production, area

harvested, and yield per hectare are based on an

index value of 1966 = 100.

National statistical organizations do not

produce data on area and production under

different rice ecosystems. The basic source of

IRRI’s information on rice areas by ecosystem is

the surveys by R. and E. Huke 1 . The data are

estimates from the returns of agricultural

censuses and available Landsat imagery and

other maps.

Some estimates of rice yields for different

ecosystems are from personal communications

with national agricultural research scientists and

outposted IRRI scientists. To make the data

consistent with total rice production for a

country, as published by FAO, we used the

yields reported by the national system for the

minor ecosystems and used the residual as the

yield from the major ecosystem. Production

figures for each ecosystem were derived from

area and yield estimates.

Some general information about the various

countries was taken from the World Factbook

2000 (U.S. Central Intelligence Agency) 2 and The

World Guide 2001/2002 3 .

All other information is from the FAO Agrostat

database and from statistical publications of

individual countries.

Note that in the General Information section

for each country, GNI is gross national income. It

is a new term for what was formerly referred to

as GNP (gross national product). PPP is

purchasing power parity. PPP compensates for

the fact that prices of many commodities or

services differ between countries. If country A

has lower (higher) prices than in the base country

(usually the United States) for comparable items,

the purchasing power of any given quantity of

money will be greater (less) in country A than in

the United States, and the GNI in PPP$ of

country A will be higher (lower) than its GNI.

The GNI per capita in PPP$ (as presented in the

country pages for year 2000) is a better measure

of income than GNI when comparing levels of

material well-being across countries.


Huke RE, Huke EH. 1997. Rice area by type of culture: South, Southeast, and East Asia, a revised and updated data base. IRRI, Manila.


Web site:


New Internationalist Publications, Oxford, England.

60 Rice almanac

Rice and food security in


Asia accounts for 90% of the world’s

production and consumption of rice

because of its favorable hot and humid

climate. Rice continues to be grown on numerous

tiny farms primarily to meet family needs. The

harvest fluctuates widely because of droughts,

floods, and typhoons. Maintaining self-sufficiency

in production and stability in prices are

important political objectives in most Asian

countries. China, India, and Indonesia account

for three-fourths of global rice consumption.

Increases in yields and


Prior to the 1960s, rice yields (weight of grain

per hectare) were low and growth of rice

production in Asia was slow, originating mostly

from expansion in cultivated land. Increases in

productivity were occurring but only in the

humid subtropics and temperate zones of East

Asia, where irrigation infrastructure was already

developed. The varieties grown were not

fertilizer-responsive and the relatively poor

market infrastructure contributed to the low-level

application of chemical fertilizers.

The 1960s were characterized by a

prevailing mood of despair regarding the world’s

ability to cope with the food-population balance.

The cultivation frontier was closing in most

Asian countries, while population growth rates

had accelerated because of rapidly declining

mortality rates.

Despite dire predictions at that time, most

Asian countries have done remarkably well so

far in meeting food needs of their growing population.

But this is primarily because those concerns

regarding the food shortages mobilized

financial and scientific resources for research on

food grains, which has succeeded in increasing

the productivity of limited land resources. Over

the last three decades, the Asian population has

increased by nearly 80% but rice production has

doubled (Table 1), contributing to substantial

increases in individual consumption of rice and

calorie intake. Several traditional rice-importing

countries with severe food security problems

(India, Indonesia, the Philippines, and Vietnam)

achieved self-sufficiency in rice in the 1980s and

Asia’s rice imports declined from 60% to 20%.

More than 84% of the growth in rice

production has come from an increase in productivity

of rice lands, through gradual replacement

of traditional varieties with dwarf and fertilizerresponsive

varieties developed at IRRI and in

national agricultural research institutes. The improved

varieties have enabled farmers to produce

two to three times more from the same parcel of

land. The incorporation of insect and disease resistance

into modern varieties helped stabilize

yields and reduce farmers’ dependence on harmful

agrochemicals. The reduction in crop growth

period from more than 150 days to around 110

days permitted an increase in cropping intensity

and also allowed land to be used for growing

nonrice crops in rice-based farming systems.

Without the impressive growth in productivity,

many Asian countries would have been forced to

further extend cultivation into marginal lands,

thus aggravating the problem of sustaining the

natural resource base.

Despite an increased demand for irrigation

and chemical fertilizers required for full

exploitation of the potential of improved

varieties, technological progress in rice

cultivation led to a decline of about 20% to 30%

in the cost of rice production per unit of output.

Such cost-saving allowed farmers to share the

* From the paper “Sustaining Food Security in the Asian Rice Economy: Achievements and Challenges” by Mahabub Hossain,

Economist and Head, Social Sciences Division, IRRI. This paper was prepared for the seminar on Sustainable Agriculture for the

21st Century, organized by the Indira Gandhi Agricultural University, Raipur, Chhattisgarh, India, 20-21 January 2001.

Rice around the world 61

Table 1. Production and consumption of rice, 1968-99.

Share of global Annual rate of growth Per capita rice

Region rice consumption (%/year) consumption


1968-99 (kg/year)


Area Production Yield 1968-70 1996-98

Asia 90.7 0.4 2.4 2.0 77.4 86.4

East Asia 37.8 –0.4 1.8 2.2 76.9 92.4

Southeast Asia 20.9 1.0 3.2 2.2 117.5 151.0

South Asia 30.5 0.5 2.6 2.1 72.0 83.5

West Asia 1.5 2.7 3.2 0.5 13.2 16.1

Other continents 9.3 1.0 2.4 1.4 8.3 14.1

World 100.0 0.4 2.4 2.0 47.4 57.8

Source: FAO, FAOSTAT, Dec. 2000.

Production of unmilled rice

(million t)








Rice production

Rice price

Rice prices (1999 US$)




19531959 1965 1971 1977 19831989 1995 1999


Fig. 1. Trends in world rice production and price,


benefits of technological progress with

consumers by accepting lower prices. As rice

supplies increased faster than demand, the price

of rice declined relative to that of other

commodities (Fig. 1). The decline in relative

prices for rice benefited the rural landless and

urban poor more than high-income groups and

farmers who produce a surplus of rice for sale to

the market because the former groups spend a

much larger proportion of their incomes on rice

than do the latter. As net consumers of rice, the

small and marginal producers, who form the

dominant group in most Asian rice-growing nations,

have also gained from the downward trend

in the price of rice.

Emerging trends in demand






Growth in demand for a staple grain depends on

(1) the level of per capita income, (2) the rate of

growth of the population, and (3) changes in

price relative to those of substitute grains. At low

levels of income, when meeting energy needs is

a serious concern, people tend to eat coarse

grains and root crops such as cassava and sweet

potato. At that lowest stage of economic development,

rice is considered a luxury commodity.

With increasing income, demand shifts from

coarse grains and root crops to rice. At high levels

of income, rice becomes an inferior commodity

and consumers prefer diverse foods with

more protein and vitamins, such as vegetables,

bread, fish, and meat.

Growing urbanization that accompanies economic

growth leads to changes in food habits

and the practice of eating away from home,

which further reduces per capita rice consumption.

The more industrialized countries of Asia,

such as the Republic of Korea, Japan, and

Taiwan (China), have passed through the phases

of demand shifts and have experienced a decline

in per capita rice consumption after reaching

high levels several decades earlier (Fig. 2).

Malaysia and Thailand are undergoing the same

experience. But these high- and middle-income

countries account for less than 10% of total rice

consumption in Asia.

The annual income threshold at which consumers

start substituting rice for higher quality

and more varied foods is estimated at around

US$1,500. This income threshold has not yet

been reached in Bangladesh, China, India, Indonesia,

Myanmar, the Philippines, and Vietnam.

These countries account for more than 80% of

total rice consumption and are going to dominate

the future growth in demand. Per capita grain

consumption in some of these countries is still

lower than the peak levels reached by the

Republic of Korea and Japan during their early

phase of development (Table 2). In South Asia

and in the Philippines and Vietnam, 30% to 50%

62 Rice almanac













Korea, Rep. of






1961-631967-69 1973-75 1979-811985-87 1991-931997-98


Fig. 2. Trend in per capita cereal consumption,

selected Asian countries, 1961-98.

of the people live in poverty and do not have adequate

income to acquire the food needed for a

healthy, productive life.

However, the major force behind the future

increase in demand for rice is going to be the

increase in population. The Asian population is

expected to increase by 35% over the next

quarter century (Table 2). In the low-income

countries where per capita consumption is expected

to continue to grow, the population is also

projected to increase by more than 30%.

The demand for marketed surplus will

increase faster because of rapidly expanding urban

societies that will generally increase the demand

for high-cost and convenience foods. The

question is whether there is enough unexploited

production capacity within the existing technology

and enough incentives for the producers

within the existing input-output price differential

to achieve the required increase in rice production

and marketed surplus of rice.

Emerging trends in supply

The experience of the last three decades created

a sense of complacency regarding Asia’s ability

to meet the growing demand for rice. Recent

trends in the growth in rice prod-uction raise

serious concern regarding the sustainability of

past achievements. Since the mid-1980s, rice

production has increased at only 1.7% per year

versus 3.2% during 1975-85 and 2.9% in the

decade earlier. Rice production has failed to

outpace population growth in many countries

(Table 3). Several factors combine to indicate

that this is the beginning of a long-term trend

rather than a cyclical downswing.

Constraints to further growth in

rice production

Technology progress running out of


The Green Revolution that began in the mid-

1960s has been successful mostly in the irrigated

ecosystem where yield increased from 3.0 to 5.8

t/ha over the last three decades (Fig. 3). Almost

all this land has already been covered with mod-

Table 2. Projections of population growth in major rice-producing and -consuming countries in Asia, 1995 to 2025.


Country Population Annual growth rate population Percent

2000 (% per year) in 2025 increase


1995-2000 2020-25

(million) 2000-25

China 1,277.6 0.9 0.5 1,480.4 16

India 1,013.7 1.6 0.9 1,330.4 31

Indonesia 212.1 1.4 0.8 273.4 29

Bangladesh 129.2 1.7 1.0 178.8 38

Vietnam 79.8 1.6 1.1 108.0 35

Thailand 61.4 0.9 0.5 72.7 18

Myanmar 45.6 1.2 0.8 58.1 27

Japan 126.7 0.2 –0.5 121.2 –4

Philippines 76.0 2.1 1.1 108.3 42

Korea, Rep. of 46.9 0.8 0.3 52.5 12

Pakistan 156.5 2.8 1.5 263.0 68

Asia (excl. China) 2,045.0 1.7 1.0 3,242.7 35

Source: United Nations, 1999. World Population Prospects: The 1998 Revision.

Rice around the world 63

Table 3. Population growth versus rice production in selected countries, 1965-2000.

Growth in

Rice harvested Population growth rice production

Country area in 2000 (%/year) (%/year)

(000 ha)

1965-85 1985-2000 1965-85 1985-2000

India 44,600 2.2 1.9 2.9 2.6

China 30,508 1.9 1.2 3.3 1.0

Indonesia 11,523 2.3 1.6 5.3 1.8

Bangladesh 10,470 2.8 1.7 1.8 1.7

Thailand 10,000 2.6 1.2 2.7 1.5

Vietnam 7,650 2.3 1.9 2.7 5.2

Myanmar 6,000 2.2 1.2 3.9 2.7

Philippines 3,900 2.8 2.2 3.8 1.8

Japan 1,800 1.0 0.3 –1.4 –1.1

Korea, Rep. of 1,059 1.8 0.9 2.6 –1.0

Malaysia 674 2.5 2.4 1.7 1.0

World 153,458 1.9 1.5 2.9 1.3

Source: FAO, FAOSTAT database, Dec. 2000.

Yield (t/ha)


Irrigated (40%)

Largely irrigated (30%)

5 Rainfed (30%)






1967 1970 19731976 1979 1982 1985 1988 1991 1994 1997



Average yield (t/ha)

Growth rate (%/yr)

1967-69 1984-86 1995-97 1967-85 1985-97

Irrigated 3.2 5.0 5.7 2.7 (0.2) 1.3 (0.1)

Largely irrigated 1.6 2.4 3.3 2.2 (0.2) 2.7 (0.2)

Rainfed 1.5 1.8 2.1 0.9 (0.3) 1.8 (0.3)

Note: The numbers within parentheses are the standard error of the

estimated growth rate. Source: IRRI World Rice Statistics and FAOSTAT

database, 2000.

Fig. 3. Trend in rice yield under different growth

conditions, 1967-97. Table gives comparative rates

in selected periods.

ern varieties and the best farmers’ yields are already

approaching the potential that scientists are

able to attain with today’s knowledge in that environment.

With intensive monoculture of rice in

the irrigated systems using high doses of indus-

trial chemicals, the natural resources are under

stress, and scientists find it difficult to sustain the

high yields. In Japan and the Republic of Korea,

rice yield has remained stagnant at around 6.0 to

6.5 t/ha after reaching that level in the late 1960s

and mid-1970s, respectively. In the humid

tropics, the maximum achievable yield on farms

is less than 6.0 t/ha because of increased pest

pressure, frequent cloudy days with below-optimal

sunshine, and susceptibility of the crop to

floods, droughts, and strong winds. In regions

with good irrigation infrastructure, this potential

yield “ceiling” is about to be reached.

Some technologies are being developed that

may help raise land productivity and input-use

efficiency in the irrigated ecosystem, and thereby

contribute to a further increase in rice supplies.

In 1989, IRRI began to design a new rice plant,

one that would make it possible to grow an irrigated

rice crop with up to 30% higher yield. It is

designed to increase nutrient efficiency with

fewer, larger panicles per plant, to reduce unproductive

tillers, and to increase photosynthesis

efficiency through erect and thick leaves. Field

evaluations of the breeding lines have been going

on for some time with new problems, such as

poor grain filling and high incidence of stem

borer, being detected. The new plant architecture

also needs to be matched with agronomic practices:

planting method, nitrogen application, and

weed control. It may take a few more years

before this technology reaches farmers.

Another available technology is hybrid rice

64 Rice almanac

for the tropics. The hybrids have a yield

advantage of 15% to 20% over the currently

inbred high-yielding varieties. Rice hybrids were

developed in China. The increase in rice yields in

China during 1975-90 was due largely to the

diffusion of hybrid varieties to 50% of the rice

area. The Chinese hybrids are not suitable for the

tropical climates in Southeast and South Asia.

IRRI scientists have developed suitable hybrid

lines for the tropics and these are now being used

by scientists in India and Vietnam to develop

varieties for release to farmers. However, with

the high cost of seeds and low prices (because of

inferior grain quality), hybrid rice varieties do

not have an advantage over the high-yielding

varieties with regard to profitability. This will

constrain the adoption of hybrid rice by farmers

unless breeders are successful in developing better

quality hybrids with higher heterosis. Another

constraint may be that, when using hybrids,

farmers need to change seeds every season,

which is an unconventional practice.

Yields in the rainfed ecosystem have increased

only marginally, from 1.4 to 2.1 t/ha over

the last few decades. There is a vast potential for

increasing production from the rainfed system by

reducing the large yield gap. But rice scientists

have yet to succeed in developing appropriate

high-yielding varieties that can withstand prolonged

drought, temporary submergence, and

other climatic stresses common in the fragile

rainfed environments. The probability of success

in making scientific breakthroughs in this area is


Growing scarcity of land and water

Natural resource constraints to increasing rice

production are becoming severe for most of the

low-income countries in Asia. The per capita

availability of arable land has been declining

rapidly with growing populations. China now

supports 17 persons per hectare of arable land,

Bangladesh 13, Vietnam 11, and India, Indonesia,

and the Philippines 8 to 10. Only Thailand,

Myanmar, and Cambodia have favorable endowments

of land, with 2 to 4 persons per hectare.

The area under rice cultivation is expected

to decline with economic prosperity and

urbanization as the demand for land for

nonagricultural uses increases. There will also be

economic pressure to release rice land in favor of

vegetables, fruits, and fodder, whose markets

become stronger with economic progress.

The scope for further irrigation of rainfed

lands is limited because of the increasing cost of

irrigation and environmental concerns regarding

its adverse effects on waterlogging, salinity, fish

production, and the quality of groundwater.

Water is also becoming a scarce commodity.

In absolute terms, annual water withdrawals are

by far the greatest in Asia, where agriculture

accounts for 86% of total annual withdrawal

compared with 38% in Europe and 49% in North

and Central America. The per capita availability

of water resources declined by 40% to 60% in

most Asian countries during 1955-90 and is

expected to decline further.

Sustaining interest in rice farming

Even if all the physical and environmental

constraints to production are overcome, many

countries of South and Southeast Asia will still

face the problem of sustaining farmers’ interest

in rice cultivation. The expansion of industry and

the services sector in urban areas, increasing

nonfarm activities in rural areas, and rapidly

rising labor productivity are contributing to a

long-term upward trend in wage rates. In Japan,

Taiwan (China), and the Republic of Korea,

rural-urban migration of the agricultural labor

force has caused a continuous decline in the

farming population, making it difficult to sustain

rural communities in some areas.

The increasing cost of rice production in

middle- and high-income countries is preventing

them from exporting surplus rice that has

resulted from declining domestic consumption.

Instead, it has lowered production. In Japan, the

rice harvest reached 18.8 million t in 1967, after

which it gradually fell to 10 million t in 1999. In

Taiwan (China), the harvest reached 3.6 million t

in 1976, whereas current production is below 2.0

million t. Meanwhile, growing scarcity of land,

labor, and water continues to drive up the cost of

rice production in spite of more efficient use of

inputs (through improved crop management

practices) and saving of labor (through mechanization).

The unit cost of production is 10 times

higher in Japan and seven times higher in the

Republic of Korea than in Thailand and Vietnam,

the major rice exporters in the world market

(Table 4). The Japanese government has encouraged

farmers to divert rice land to other crops,

but not all rice land is suitable for other crops.

Rice around the world 65

Table 4. Comparison of domestic rice prices and the cost of rice

production in selected countries, 1987-89.

Paddy yield Cost of Domestic farm-

Country (t/ha) production gate price of

(US$/t) paddy (US$/t)

Japan 6.5 1,987 1,730

Korea, Rep. of 6.6 939 957

USA 6.3 220 167

Vietnam 4.6 100 130

Thailand 1.8 120 141

Philippines 2.6 124 160

Indonesia 5.8 118 132

Bangladesh 4.6 138 180

Source: IRRI for Bangladesh and Vietnam. For other countries, FAO, Economic and Social

Development Paper 101, Rome, 1991.

Under political pressure from farm lobbies, the

government had to protect the domestic rice market

by increasing prices and providing farm subsidies,

to keep a balance between incomes of rice

farmers and incomes of urban labor households.

Rice production had been adjusted to domestic

demand through manipulation of trade, pricing,

and subsidy policies.

Ongoing negotiations within the World

Trade Organization related to liberalizing rice

trade may further dampen incentives for rice

production, particularly in these middle- and

high-income Asian countries. Large land-surplus

countries (e.g., Australia, United States) can reap

economies of scale using modern technology

(such as mechanization and precision farming

methods) because of the large size of rice farms.

If domestic markets in middle- and high-income

Asian countries are opened for competition, the

price of rice will decline substantially, providing

incentives to consumers to acquire imported food

staples and forcing farmers to abandon rice cultivation

in favor of more lucrative economic activities.

An important way of gaining competitive

strength in the face of liberalization of rice trade

is by consolidating tiny holdings into large

farms.“Smart farming” in large-scale holdings,

as currently practiced in developed countries,

may contribute to vertical integration of the rice

industry, more efficient use of machinery, and a

reduction in the large number of part-time farmers

whose income must be maintained at least at

the level of urban labor households. The main

constraint to the consolidation of holdings into

efficient and competitive large-scale farming in

Asia is the high price of land.

Sustaining food security

Food security means access by all people at all

times to adequate food required to live an active,

healthy life. Its essential elements are both

availability of food and the ability of the people

to acquire it. National self-sufficiency in food

may not ensure food security because the poor

may not have enough income to buy adequate

food. India, for example, is self-sufficient in rice

because it does not need to import it. Yet, onethird

of the Indian population cannot afford to

buy basic food. Maintaining a stable supply of

basic staples (through production or imports) at

affordable prices for the poor, while maintaining

incentives for production growth for farmers, is a

key element in sustaining food security.

Obviously, a country does not need to be

self-sufficient in domestic food production to

achieve or sustain food security. Singapore and

Hong Kong (China) produce very little food but

have better records of food security than the

major rice-growing countries in the region.

Malaysia meets almost one-quarter of its rice

needs through imports. It is a prudent policy

because Malaysia maintains domestic production

with subsidies; resources tied up in rice

cultivation can be used more productively in alternative

economic activities. What is important

for food security is achieving food self-reliance.

This requires (1) a favorable export growth at the

national level, permitting food-deficit countries

to import food from food-surplus countries that

can produce it at a lower cost; and (2) at the

household level, developing productive

employment that enables the population to buy

adequate food. Most countries in East and

66 Rice almanac

Southeast Asia are fortunate in this respect. With

growing economic prosperity and alleviation of

poverty, they are able to fulfill these conditions.

In fact, as the cost of rice production increases

with growing wage rates, land prices, and

scarcity of water, it makes sense to readjust

resources away from labor-intensive rice

cultivation, if improving economic efficiency is

the primary consideration.

But what will happen if every country in

Asia abandons the production of staple grains

and reallocates resources to more profitable economic

activities and opts for sustaining food security

through international trade? In Japan and

the Republic of Korea, consumers now pay for

domestic rice a price many times higher than that

in the world market. But, who will produce the

exportable surplus for them? Will rice supply to

the world market increase substantially in

response to higher prices? What would be the

political response in rice-exporting countries to

international transactions in staple food when

trade generates scarcity in the domestic market?

What would be the impact of rising food prices

on inflation and other macroeconomic variables?

The answers to these questions have important

implications for the strategy for sustaining food

security through trade for the affluent Asian nations.

The international rice market is very small.

Only 6–7% of the crop is traded in the world

market versus 20% for wheat and 11% for coarse

grains. Unpredictable floods, droughts, and typhoons

cause shortages and surpluses from year

to year. These produce wide fluctuations in marketable

surplus and import needs. However, the

world rice market is becoming less volatile.

The other factor to consider is the influence

of the giant economies of Asia—China and

India—on the world rice market. The volume of

international trade is equivalent to only 13% of

rice consumption in China, or 8% of the

combined consumption of India and China. If

these countries decide to meet only 5% of their

rice needs through imports, the additional

demand would swamp the world market. When

rice production in Japan fell by 25% because of

abnormal weather from October 1993 to April

1994, the price of quality rice in the world market

surged in response.

Given an adequate increase in rice prices,

there is some potential for expansion of the ricegrowing

area in the humid tropics of Africa,

where only 15% of 20 million hectares of

potentially suitable rice land is currently cultivated,

and in Latin America, which has an additional

20 million hectares of land suitable for

rice. The unit cost of production and the marketing

margin are many times higher in Africa and

Latin America than in Asia, and the demand for

rice has been growing faster in other continents

than in Asia, so the exportable surplus available

for Asia from these continents could be quite


Only Myanmar and Cambodia could

produce an additional exportable surplus to meet

potential shortages in other Asian countries and

this would require substantial investment for

land reclamation, expansion of irrigation, technologies

for improvement in rice quality, and

development of marketing infrastructure. Also,

any gains may be offset by likely declining

exports from Thailand and Vietnam, as farm

wages and the opportunity cost of family labor

increase in Thailand, and as internal demand

grows in Vietnam.

Provided there is free trade in rice, highincome

food-deficit countries can always acquire

rice from the market, even when there is scarcity,

because they can afford the resulting higher

prices. It is the poor consumers in low-income

countries who will suffer when there is a scarcity

and it will have far-reaching effects on their domestic

economy. Since rice is a major component

of the food basket, the increase in prices will

contribute significantly to inflation and put

upward pressure on industrial wages, as the organized

labor force bargains for sustaining

growth in real incomes. Industrial profits will

shrink and the competitive strength of the

economy in the production of labor-intensive

goods will erode.

These are the reasons why rice is regarded

as a strategic commodity in Asia, and why maintaining

stability in rice prices is a key political

objective for the government in many lowincome

countries. When prices soar, the

government may intervene in the market to protect

the interest of the nation. Imposing a ban on

exports of staple foods when there is a scarcity in

the domestic market is not a rare phenomenon.

Thus, it is in the interest of every nation to

sustain a safe capacity of domestic production of

staple food, whatever the cost of production.

Rice around the world 67

Rice in Europe and the


Rice in Europe is grown under a

Mediterranean climate characterized by

warm, dry, clear days and a long growing

season favorable to high photosynthetic rates and

high rice yields. Compared to tropical and

subtropical rice-growing areas, the climate is

cool, but warm summer nights during panicle

development, when pollen formation takes place,

help to avoid cold-induced floret sterility. Low

relative humidity throughout the growing season

reduces the development, severity, and

importance of rice diseases. However, cool

weather and strong winds during stand

establishment may cause partial stand loss and

seedling drift.

Rice is mostly grown on fine-textured,

poorly drained soils with impervious hardpans or

claypans. These soils are principally in three

textural classes: clays, silty clays, and silty clay

loams ranging from 8% to 55% clay. A few of the

soils are loam in the surface horizon but are

underlain with hardpans. The pH is from 4 to 8

and organic matter from 0.5% to 10% (this last

value on only a limited surface area). These soils

are well suited to rice production because their

low water permeability enhances water-use

efficiency. In some regions (the Camargue in

France and Ebro Delta in Spain), soils are saline

or very saline. Most of the irrigation water for

European rice comes from rivers (the Po in Italy,

Ebro in Spain, Rhone in France, Tejo in Portugal,

etc.) and lakes. It is estimated that less than 5% of

rice irrigation water is pumped from wells—in

areas where surface water is not available or as a

supplement to surface supplies. The high cost of

pumping well water prevents its widespread use

in rice production. Surface water and most

groundwater are of very good quality for rice


In all European countries, rice is commonly

cultivated with a permanent flood with short

periods during which soil is dried to favor rice

rooting (in the early stages) or weed control

treatments. The conventional irrigation system is

also known as a “flow-through” system because

water is usually supplied in a series from the topmost

to the bottom-most basin and is regulated by

floodgates by means of removable boards.

The main rainfalls occur during the first

stages of the crop (April-June) and during the

harvesting period. Average temperatures range

from 10–12 °C during rice germination to 20–25

°C during crop flowering.

Seedbeds are commonly prepared by plowing

in autumn or springtime at a depth of 20 cm and

incorporating residues of the previous crop into

the soil. To favor weed germination to control

weeds better before rice planting, the soil is

sometimes prepared by adopting minimum tillage

practices. Precision land grading, obtained with

laser-directed equipment, is an agronomic

practice that has greatly contributed to better

water management, and consequently to better

crop stand establishment and weed control.

Fertilization is mostly aimed at restoring the

main plant nutrients removed by crops. Because

of flood conditions, nitrogen is principally

absorbed in ammoniac form. This nutrient is

commonly supplied at 80–120 kg/ha, 50% in

preplanting and 50% in postplanting, using urea

or other ammoniac fertilizers. Phosphorus and

potassium are supplied entirely in the preplanting

stage at 60–80 and 100–150 kg/ha, respectively.

About 80% of the rice area is cultivated with

japonica varieties and the remainder with indica

or indica-type varieties (mainly Thaibonnet). Rice

is planted from mid-April to the end of May and

harvested from mid-September to the end of

October. Since the beginning of the 1960s, rice

*Contributed by Mr. Aldo Ferrero, Dipartimento di Agronomia, Selvicoltura e Gestione del Territorio, Via Leonardo da Vinci, 44,

10095 Grusliasco (TO), Italy.

68 Rice almanac

Main areas of rice cultivation

in Europe



Po Valley



Thessaloniki area



Ebro Delta




has been direct-seeded mechanically. Most is

broadcast-planted in flooded fields and only

40,000 ha (almost all in Italy) are row-planted in

dry soil. Rice planted in dry soil is commonly

managed as a dry crop until the crop reaches the

3–4-leaf stage; after this period, the rice is

flooded as in the conventional system with

continuous flooding. In these conditions, rice has

no competitive growth advantage over weeds,

which can compete with the crop from the

beginning of stand establishment.

During rice cultivation, water is commonly

kept at a depth of about 4–8 cm and drained away

2–3 times to improve crop rooting (about 20 days

after planting), to reduce algal growth, and to

allow application of herbicides, which require dry

soil. Rice fields are commonly drained toward the

end of August to allow harvesting.

Rice yield is frequently affected by infestation

of animals, fungus diseases, and weeds. The

main animal pests are crustaceans such as Triops

cancriformis and insects such as Hydrellia

griseola, Limonia modesta, Chironomus cavazzai,

Donacia dentata, and Rhopalosiphum padi, which

are commonly controlled with soil drainage or

organophosphorus products. The main fungus

diseases are Rhizoctonia spp., Pythium spp.,

Pyricularia oryzae, and Drechslera oryzae. These

diseases are controlled by treating crop seeds with

iprodione, carbendazim, and mancozeb, spraying

rice plants with tricyclazole (against P. oryzae), or

using resistant varieties.

Weeds are reported to be the pests causing

the greatest damage to rice in Europe. The major

species are Echinochloa crus-galli, E.

phyllopogon, E. crus-pavonis, E. colona, Oryza

sativa var. sylvatica (red rice), Heteranthera

rotundifolia, H. reniformis, H. limosa, Alisma

plantago-aquatica, A. lanceolatum, Bolboshoenus

maritimus, and Schoenoplectus mucronatus.

Alisma plantago-aquatica and S. mucronatus

have shown numerous cases of resistance to ALS

inhibitor herbicides. The infestation trend of these

species is considered stable or slightly expanding

in spite of weed control treatments (commonly 2–

3 applications). Without weed control, crop losses

at a yield of 7 to 8 t/ha were estimated to be as

high as 92%.

The main herbicides applied for weed control

are against Echinochloa spp.: molinate, propanil,

thiocarbazil, dimepiperate, quinclorac, cyhalofopbutyl,

and azimsulfuron; against Heteranthera

spp.: oxadiazon; against Alismataceae and

Cyperaceae species: bensulfuron-methyl,

cinosulfuron, ethoxysulfuron, azimsulfuron,

metosulam, MCPA, and bentazone. Red rice is

controlled with a combination of preventive,

cultural, and chemical practices. The most

common preventive means are planting certified

and weedy-rice-free seed or turning to rotational

crops such as maize or soybean. The cultural

practices are mainly based on the adoption of the

stale seedbed practice, applied by preparing the

seedbed early in the season (March) and then

Rice around the world 69

flooding the rice field to stimulate weed

germination, and late seedbed preparation using

disk harrows to destroy already emerged young

seedlings. Weed seedlings are then controlled by a

pass of a disk harrow or with dalapon, glyphosate,

or other total graminicides. Weedy rice can also

be controlled with an application of pretilachlor,

about one month before planting.

In 2000, rice was cultivated on European

Union farms on a total of about 410,000 ha. The

most important rice-producing countries are Italy

(221,000 ha), Spain (111,000 ha), Portugal

(31,000 ha), Greece (27,000 ha), and France

(19,000 ha). Spain and Greece have been the

countries where the area of rice farming has

shown the greatest change over the last 10 years,

with increases of about 24% and 68%,

respectively. The average rice yield in these

countries is 6.6 t/ha, although farm yields of 7–

7.5 t/ha are frequently recorded.

Beyond the European Union, the main

countries producing rice in the region are Egypt

and Turkey.

Rice is an important crop in Egypt, where it

occupies more than 20% of the cultivated area

during the summer season and engages about 1

million families. Rice yields in Egypt are among

the highest in the world, thanks to the fertile soil

of the Nile delta, high intensity of sunlight, few

diseases and insect pests, good irrigation system,

and a well-organized national rice research

program. The average yield has increased

dramatically in the past 15 years, from 5.7 t/ha in

1985 to 7.1 t/ha in 1990 and 9.1 t/ha in 2000. Two

of the seven rice-growing governorates (Beheira

and Garbia) yielded about 9.5 t/ha.

During the last few years, Egypt has attained

a considerable surplus of rice for export. This has

been achieved by releasing and spreading new

early and high-yielding varieties such as Giza

70 Rice almanac

175, Giza 176, Giza 181, Giza 177, Giza 178,

Sakha 101, and Sakha 102; the transfer of

appropriate technology to the farming community

to improve crop management; and the improvement

of productivity in the saline areas in the

North Delta.

The development of the rice economy has

been influenced by several policy changes

resulting from the implementation of the

economic reform program. This program is

principally based on liberalization of crop

production through cancellation of area

allotments and phasing out of input subsidies.

Despite large, optimistic land reclamation

projects, the potential for increasing the area

planted to crops is limited. The main limitation is

the availability of irrigation water, as rice is one

of the most water-consuming crops.

In Turkey, rice is grown mainly in seven

geographical regions: Marmara-Thrace, Black

Sea, Central Anatolia, Southeastern Anatolia,

Mediterranean, East Anatolia, and the Aegean.

The largest production areas are in the provinces

of Edirne and Samsun.

Rice is cultivated under continuous flooding

conditions. Planting is carried out using pregerminated

seed (about 200 kg/ha) broadcast by hand

on flooded soil. Fertilization is usually done with

nitrogen and phosphorus fertilizers at 100–150

and 80 kg/ha, respectively. Potassium is normally

not supplied because of the high availability of

this nutrient in Turkish soils.

Harvesting is from mid-September to the end

of October and is commonly carried out when

rice grains reach 20–24% water content. Rice is

harvested by hand and then treshed with tresher

equipment or with a combine harvester.

The rice land areas and yields in Egypt and

Turkey and the other non-European Union

countries producing rice are shown in Table 1.

More information on European and

Mediterranean rice-growing countries can be

found in the individual country sections.

Med-Rice is the FAO Inter-Regional

Cooperative Research Network on Rice in the

Mediterranean Climate Areas. It was created in

Table 1. Rice lands and yields in non-European Union

countries, 2000.

Country Area (ha) Yield (t/ha)

Egypt 660,000 9.1

Turkey 60,000 5.6

Morocco 5,600 4.5

Romania 1,500 2.5

Russia 175,800 2.5

Bulgaria 3,000 2.3

Hungary 3,088 2.3

Source: FAOSTAT.

1990 as one of the interregional and regional

networks on rice and field projects, supported by

the International Rice Commission (IRC) and the

Rice Development Programme (RDP). The

objective of Med-Rice is to promote scientific

exchanges among rice scientists working in the

Mediterranean area and in the other regions with

a Mediterranean climate.

The network began as a response to the need

to collaborate and coordinate research on rice in

view of its increasing cultivation and

consumption in Europe. Some of the important

subjects are quality and competitiveness of

European rice; resistance to blast, stem borers,

and diseases; control of red rice, a weed that

competes with cultivated rice; cataloguing of rice

genetic resources in the region; and a databank of

knowledge on all aspects of rice cultivation for

the purpose of improved management and rice

yields. These are all being investigated through

cooperative research programs among member

institutions of the network.

Twelve countries participate in Med-Rice:

Egypt, France, Greece, Hungary, Italy, Morocco,

Portugal, Romania, Russia, Spain, Turkey, and

the United Kingdom. Activities of Med-Rice

include scientific meetings, cooperative research

programs, and publications ranging from reports

and proceedings to a newsletter (Medoryzae).

Scientific activities fall under five working

groups, on agronomy, biotechnology, economy,

selection, and technology. The network has its

own Web site (

Rice around the world 71

Rice in North America

Rice in North America is grown in the

United States and Mexico. “Wild” rice,

not a true rice but sometimes grown in the

same manner as real rice, occurs in southern

Canada and the U.S., and is mentioned briefly

here. The following description focuses on the

major producer, the U.S.

The United States *

The U.S. population was approximately 276

million in 1999. The country is highly

industrialized. The populace is employed

principally in manufacturing and service

industries, with only 2% directly involved in

forms of agriculture, which itself makes up 2% of

the gross domestic product. The 1997 Census of

Agriculture reported a total of 9,291 farms that

produced rice that year.

Carolina Gold, the first rice variety

Carolina Gold was the first rice variety to be

grown commercially in what is now the United

States. It is thought to have arrived in 1681 when

a ship from Madagascar took shelter in Charles

Towne (now Charleston, S.C.) during a storm.

The ship’s captain left a bag of rice seeds he had

collected in Madagascar. The seeds thrived and

became known as Carolina Gold. A sister

selection was called Carolina White. The Gold

Coast of South Carolina and Georgia was named

because of the golden fields of rice that ships saw

when approaching the coast. Exports of the

Carolina rice made Charles Towne the wealthiest

city in England’s American colonies. The vast

Carolina rice plantations disappeared after the

U.S. Civil War (1861-65) and so did the Carolina

sisters. But, in the 1990s, scientists of the Centro

Internacional de Agricultura Tropical (CIAT)

found Carolina Gold and White growing along

the upper Amazon in South America.

U.S. rice production in 1999-2000 was 9.3

million t, accounting for about 1.5% of total

world production. The rice was grown on 1.42

million ha with an average yield of 6.6 t/ha.

Rice is grown in seven states, but three

states—Arkansas, California, and Louisiana—

together account for about 80% of U.S. rice area

and production.

Arkansas is the main U.S. rice-growing state,

producing about 46% of U.S. production.

Arkansas harvested 4.3 million t on 660,000 ha in

1999. California was second, harvesting 1.7

million t on 206,000 ha; followed by Louisiana,

1.4 million t on 251,000 ha; Mississippi, 0.8

million t on 132,000 ha; Texas, 0.7 million t on

105,000 ha; and Missouri, 0.45 million t on

75,000 ha. Florida and some other states also

grow small amounts of rice.


The U.S. exported about 2.8 million t of rice,

mostly milled, in 2000. That is about 12% of all

world exports, making the United States the

fourth largest exporter of rice (after Thailand,

Vietnam, and China).

The main markets for U.S. rice are Canada,

Haiti, Japan, Mexico, Saudi Arabia, and Turkey.


Although low compared with most Asian

countries, U.S. rice consumption more than

doubled over the past 20 years, to an all-time high

of 12.3 kilograms per person in 2000.

Direct food use accounts for 63% of U.S.

consumption; processed foods, including pet food

and baby food, 22%; and beer, 15%.

Part of the increase in direct food use is

because of a general interest in rice for improving

diet and health, plus marked increases in Asian

and Hispanic populations, who prefer rice.

Imported rice constitutes 11% of direct food

*Contributed by Dr. Thomas Hargrove.

72 Rice almanac







Rice-growing areas

Map courtesy of Dr. T. Hargrove.

consumption; most is aromatic Thai jasmine and

Indian and Pakistani basmatis, consumed by

ethnic Asians. Arborios are also imported from



The brewing company Anheuser-Busch is the

largest purchaser of U.S. rice, buying about 8% of

the annual crop. The brewing giant owns its own

rice mills in Arkansas and California. Budweiser,

its most popular beer brand, uses rice as an

adjunct. Rice and corn flour are used in other

Anheuser-Busch beers. Coors is also a rice-based


Wild rice

American “wild rice,” favored by gourmets, is not

rice at all; it is Zizania aquatica, a semiaquatic

grass native to the Great Lakes region of the U.S.

and Canada. Native North Americans have

gathered and eaten wild rice for thousands of

years. The early native inhabitants of the Great

Lakes region increased the natural production of

wild rice by rolling seeds into a ball of clay and

dropping the seeded balls into the water. It is still

harvested wild, although domestication in

Minnesota began in the 1950s—perhaps the first

cereal to be domesticated by humans since the

time of the Pharaohs.

Wild rice came to California in 1972 when a

rice farmer in northern California’s Sacramento

Valley planted some seed brought from

Minnesota in an ice chest. Commercial

production began in 1977. Wild rice is now being

grown commercially in Minnesota, California,

Utah, and Oregon, and in Canada. In the U.S.,

wild rice is now grown in much the same way as

“real” rice, in flooded fields, with yields of up to

1.6 t/ha in Minnesota and twice that amount in

California reported in the early 1990s. In Canada,

commercial production is mainly from leased

lakes that are seeded; the leaseholder is given

exclusive harvesting rights and much of the

harvesting is done using airboats.

Rice environments

The rice production data above show that rice in

the U.S. is grown in three principal areas: the

Grand Prairie and Mississippi River Delta of

Arkansas, Louisiana, Mississippi, and Missouri

from 32° to 36° N; the Gulf Coast of Florida,

Louisiana, and Texas from 27° to 31° N; and the

Sacramento Valley of California from 38° to 40°

N. The climate varies from semiarid California,

Rice around the world 73

Large-scale mechanized rice farmers in the United States use equipment such as this minimum till air drill

that plants 65 rows at a time with a holding capacity of 10,000 pounds of seed. Source: Jay Cockrell, Texas

Rice Newsletter.

with less than 50 mm of rainfall during the

growing season, to the humid subtropical Gulf

Coast of Louisiana, Texas, and Florida, where

rainfall may total 700–1,000 mm. In all these

environments, rice is grown as a single crop per

year, but can be ratooned in the warmest,

southernmost regions of the Gulf Coast states.

Approximately 40% of Texas and

southwestern Louisiana rice area is ratooned

annually. All rice in the U.S. is irrigated and

direct-seeded. In California, pregerminated seed

is seeded into standing water by aircraft.

Southwestern Louisiana is also wet-seeded. Dry

seeding with a mechanized grain drill is the most

common method of planting in the southern U.S.

Rice is grown on natural flatlands. Nearly

100% of these flatlands in California and

approximately 40% in the southern U.S. have

been further leveled by laser-directed machinery.

In rice monocrop systems, the land may be

leveled to a slope of 0.02 to 0.05 m/100 m. In

rice–row crop systems, grades of 0.1 to 0.2 m/100

m are required for drainage or irrigation of the

rotation crop. Precision leveling has greatly

facilitated water management and is considered

second only to the introduction of semidwarf

varieties as contributing to increased rice yields.

In California, where the rain-free

environment and high latitude provide maximum

solar radiation and low disease pressure, farm

yields average 8–9 t/ha. In the humid southern

rice environments, disease (primarily blast and

sheath blight), warm nights, cloudy days, and

frequent thunderstorms at heading limit average

yields to about 6.5 t/ha.

74 Rice almanac

Problems and opportunities

Although U.S. yields are high, several problems

constrain production.

• In the humid subtropical climates of the

Gulf Coast and Mississippi River Delta

areas, diseases (particularly blast and

sheath blight) limit yields.

• Because all areas are direct-seeded, weeds

and poor stand establishment are

significant problems.

• In the southern U.S., many share-crop

arrangements are short term and tenant

farmers are reluctant to spend capital for

long-term improvements to productivity.

• An indirect production constraint is

embodied in concern about agriculture’s

role in environmental degradation. All

U.S. agriculture now operates within a

stringent and costly regulatory

environment. One critical concern is

maintaining high-quality surface water and

groundwater with respect to potable water,

the health of aquatic organisms, and

recreational uses.

• In some areas, especially California,

degradation of air quality from burning

rice straw is highly regulated and rice

straw disposal is a production problem.

Rice research and extension are an integral

part of the U.S. Department of Agriculture and

University Land Grant system, supplemented by

private research and development, primarily by

commercial seed and agricultural chemical

producers. All of the principal rice-growing states

have well-staffed and equipped public-sector rice

research stations. Scientific exchange among

these institutions is linked by the U.S. Rice

Technical Working Group. Linkages to IRRI and

other international programs on rice are scientistto-scientist,

mostly on an ad hoc basis.

The challenges for U.S. rice production are

to maintain high yields and quality as well as the

sustainability of the rice-based cropping system,

in the context of maintaining and improving soil,

air, and water quality in an increasingly regulated

environment. Improved technology and

equipment for land and irrigation management

and for harvesting and handling high-quality rice;

varietal improvement through the integration of

genetic engineering and conventional breeding

programs; integrated pest and crop management;

and the development of sophisticated pest control

technology will be key elements in future

production opportunities.

Summary data on U.S. rice production are

given on page 231.


Maize is the main staple of the 97 million

inhabitants of Mexico, but the country produces

about 450,000 t of rice annually. Rice is grown in

at least 17 states, the three major states being

Sinaloa, Campeche, and Veracruz, each of which

contributes a little over 20% of the nation’s total

rice production. Other states producing significant

amounts of rice (2% to 6%) are Tabasco, Colima,

Tamaulipas, Morelos, Nayarit, Michoacán, and


Production has varied over the past two

decades with little discernible trend. Annual

production in 1980, 445,000 t, was almost the

same as that in 2000. However, the harvested area

has decreased from 127,000 ha in 1980 to 98,000

ha in 2000, indicating a gradual improvement in


Consumption of rice is low, about 8 kg per

capita per year, but is not sustained by domestic

production. Imports of rice grew from less than

100,000 t in 1980 to more than 400,000 t in 1999,

almost equal to national production. Most is

imported from the U.S., for which Mexico is the

largest export market.

More details on Mexican rice production are

given on pages 194-195.

Rice around the world 75

Rice in Latin America and

the Caribbean

Rice is a staple food crop in Latin America

and the Caribbean (LAC). The region’s

per capita annual consumption increased

from about 9 kg of milled rice in 1924-28 to

about 30 kg in 1993-95. Rice consumption is

concentrated in the tropical countries of the

region, which have a total population of 320

million. About 40% live below the FAO poverty

line. Tropical Latin Americans consume an

average of 37 kg of milled rice yearly—equal to

about 1.3 cups of cooked rice daily. After sugar,

rice is their single most important source of daily

calories, supplying 11.5% of daily caloric intake.

In Brazil, Colombia, Panama, Guyana, and the

Dominican Republic, rice provides 25% more

calories than any other crop.

Rice is also a leading source of protein for

the poorest 20% of the tropical population,

supplying more per capita than beans, beef, or

milk. Rice is income elastic in the region:

consumers tend to increase consumption as their

incomes rise.

From 1967 to 1995, increasingly efficient

production, triggered by the adoption of modern

semidwarf varieties that were more inputsensitive,

caused the real price of rice to decline

by 50%. Massive resulting social benefits went to

the urban poor. Rice is particularly important

from the standpoints of growth and equity. Rice is

preferred by the poor because it is cheap,

nutritious, appealing, easy to prepare, and easy to

store and transport.

Poverty in Latin America and the Caribbean

is extensive: 31% of the total population is poor

and 21% is desperately poor. Most of the poor

live in urban areas. Poor urban dwellers spend

about 15% of their income on white rice—their

cheapest source of energy, carbohydrates, and

protein. Their well-being is therefore affected by

the amount, quality, security of supply, and price

of the rice they eat.

Pushed by large debt burdens, fiscal and

trade imbalances, and high inflation rates during

the 1970s and 1980s, most of the region’s

countries have developed self-sufficiency policies

for rice production to maintain low and stable

prices for urban consumers.

Source of agricultural development

Traditionally, rice was a leading pioneer crop for

area expansion and colonization until the 1980s

when the trend in agriculture reverted to more

intensive practices as a result of more open trade

practices and the need to increase efficiency and

competitiveness. During 1990-2000, rice

production in LAC expanded annually at 3.0%

fueled by a 3.8% annual growth in yield while

cultivated area contracted annually at 0.8%. Most

of the decline in area occurred in upland rice.

Irrigated rice area continued a steady increase.

Higher yields were the result of the shift to

irrigation as well as the continuous release of

improved varieties.

Such growth in production has provided

many opportunities for reactivating local rural

economies. Moreover, local feed and food

agroindustries used nearly 4 million t of rice byproducts

per year by in the mid-1990s.

Urbanization and economic liberalization are

forcing the integration of regional rice markets

and agribusiness. Demand is increasingly high for

healthy, diversified, rice-based convenience

foods. Most countries do not rely on rice imports

to meet domestic needs.

76 Rice almanac

In 1993-95, 3.8% of the world’s rice

production and 3.4% of the cultivated area were

in Latin America and the Caribbean. From 1966

to 1995, rice production increased from 9.8

million t to 20.7 million t. In 1993-95, 6.7 million

ha in Latin America were under rice. Of these, 3.1

million ha were upland, 1.1 million ha rainfed

lowland rice, and 2.5 million ha irrigated rice.

About one million farmers in the region

depend on rice as their main source of energy,

employment, and income. Of these, about 0.8

million are resource-poor smallholders, planting

less than 3 ha. They cultivate rice manually,

producing only 6% of the total rice output in

Latin America and the Caribbean. The other 0.2

million rice growers produce 94% of the rice,

having larger (15–50 ha on average) mechanized


Geographical features of rice

cultivation in Latin America

More than two-thirds of Latin America’s arable

lands are within lowland ecosystems. Rice is well

adapted to the wet soils common in the lowlands.

Opportunities exist for lowland rice expansion in

the vast wetlands of Brazil (with a potential of 24

million ha), the Andean countries (Venezuela,

Ecuador, Peru, and Bolivia), the River Plate Basin

(Argentina, Uruguay, and Paraguay), Guyana, and

Central America.

Another ecosystem with potential is the highrainfall

savannas, with aerobic upland acid soils,

found in Brazil, Venezuela, Colombia, Bolivia,

Guyana, and Suriname. Rice is more tolerant of

acidity than are other grain crops. New

technologies (more input-responsive rice

varieties) and production systems (upland ricepasture

cultivation) can encourage the

establishment of improved pastures and relieve

pressure for food production from more fragile


Rice grown under irrigation provides 59% of

the total production on just 37% of the total rice

area, with average yields of 5.0 t/ha. For rainfed

lowland rice, the corresponding figures are 22%,

16%, and 3.9 t/ha, respectively; and for upland

rice, 19%, 46%, and 1.3 t/ha, respectively.

Brazil accounts for 65% of all the rice area in

Latin America and the Caribbean. The rice area in

Brazil is 62% upland, grown on acid soils,

whereas, outside Brazil, most rice is irrigated on

richer soils. Brazil produces 52% of all irrigated

rice, 38% of all rainfed rice, and 92% of all

upland rice in the region.

In contrast with other rice-growing regions in

the world, rice cultivation on larger farms in

tropical Latin America and the Caribbean is

predominantly mechanized. Direct seeding and

purchased inputs are used across ecosystems.

These features fit fairly well with the

characteristics of the region—abundant flat lands

and scarce labor—and enhance its comparative

advantage in efficient rice production compared

with more labor-intensive cultivation systems

elsewhere in the world.

A direct-seeded culture

In contrast to Asia, where rice is commonly

transplanted, rice in Latin America is mostly

direct-seeded, a practice that developed because

of increasing labor costs. The Asian transplanting

system is used on only 6% of the region’s total

rice area.

About two-thirds of irrigated rice lands are

minor schemes developed by farmers who divert

water from streams, rivers, and wells. The new

short-duration varieties, developed regionally, and

capital inputs and water have helped farmers deal

successfully with weed populations and with the

more demanding water, fertilizer, and pest

management needs for direct-seeded rice.

Research challenges

Environmental concerns require reduced

agrochemical use and alternatives to forest

clearing for crop production. To achieve these

objectives, rice scientists must continue working

on (1) developing higher-yielding wetland rice

varieties, (2) developing more productive

varieties for upland rice, and (3) reducing

production costs and environmental hazards

through genetically resistant varieties and better

crop management practices to achieve higher

efficiency in the use of inputs. The last point

encourages farmers to maintain or increase the

cultivated area, despite low rice prices, and to

reduce agrochemical use.

Research and development in

Latin America

Nearly 100 publicly funded agricultural research

and development institutions work on rice in

Rice around the world 77

Experimental rice plots in Uruguay.

Latin America and the Caribbean. Each follows

one of four models: (1) as part of a research

department in the Ministry of Agriculture, (2)

as part of a decentralized agricultural research

institute, (3) as an association with a rice

development project, or (4) as a decentralized

rice research institute.

Rice research is also carried out by

farmers’ organizations, private companies,

universities, and regional institutions, their

opportunities having increased since the

internationalization of most countries in the

region during the 1990s. Helping researchers to

benefit from collaboration and to improve their

capacity are networks such as INGER

(International Network for Genetic Evaluation of

Rice), FLAR (Fondo Latinoamericano de Arroz

de Riego), and CRIDNet (Caribbean Rice

Industry Development Network). Fom 1975 to

1995, 250 rice varieties were released in the

region. About 70% of these varieties were

introduced to the countries through INGER.

The high return to international and national

rice research in Latin America and the Caribbean

is equivalent to an annual interest rate of 69%.

This is extremely attractive, compared with the

interest rate of about 10% earned on commercial


78 Rice almanac

Rice in West Africa

Revolutionary change in the preferences

of West African consumers has created a

wide and growing imbalance between

regional rice supplies and demand. The major

trends in consumption, production, and imports of

rice are illustrated in Table 1. Since 1973, regional

demand has grown at 6.0% annually,

driven by a combination of population growth

(2.9% growth rate) and substitution away from

the region’s traditional coarse grains. The

consumption of traditional cereals, mainly

sorghum and millet, has fallen by 12 kg per

capita, and their share in cereals used as food

from 62% in the early 1970s to 50% in the early


In contrast, the share of rice in cereals

consumed has grown from 15% to 25% over the

same period, and from 12% to 18% in calorie

terms from the 1960s to the end of the 1990s.

Much of this dramatic shift occurred in the late

1970s and ’80s. After decreasing to around 2.5%,

per capita rice consumption has begun to increase

again at more than 3% annually since the late

1990s. Accounting for population growth, total

rice consumption has increased at nearly 6% per

year during the last five years, meaning that it

will have increased 2.5-fold by 2010.

The most important factor contributing to the

shift in consumer preferences away from

traditional staples and toward rice is rapid

urbanization and associated changes in family

occupational structure. As women enter the

workforce, the opportunity cost of their time

increases and convenience foods such as rice,

which can be prepared more quickly, rise in

importance. Similarly, as men work at greater

distances from their homes in the urban setting, a

greater proportion of meals is consumed from the

market, where the ease of rice preparation has

given it a distinct advantage.

These trends have meant that rice is no

longer a luxury food, but has become a major

source of calories for the urban poor. Urban

consumption surveys in Burkina Faso, for

example, have found that the poorest third of

urban households obtains 33% of its cereal-based

calories from rice. For that same group, rice purchases

represent 45% of its cash expenditures on

cereals, a share that is substantially higher than

for other income classes. Similar findings have

been obtained in several other West African

nations, demonstrating that rice availability and

rice prices have become a major determinant of

the welfare of the poorest segments of West African

consumers who are the least food-secure.

Production and imports

In comparison with the rapid growth in demand,

regional rice production rose at 4.6% annually

from 1973 to 2000. Although this rate was high

compared to the performance of other major

crops, it meant that regional rice production only

barely exceeded population growth, and was

meeting only two-thirds of the increments in demand.

The source of the increases in rice production

carries the important danger signal that such

growth is not likely to be sustainable. Regional

rice yields, which average only 40% of the world

mean, have risen at only 1.5% per year since

1983. The major source of growth has been the

expansion of cultivated area, which has grown at

a remarkable 3.7% annually over the period.

The widening gap between regional supply

and demand has been met by imports. The rapid

increase in demand and much slower growth in

production from 1973 to 1983 contributed to a

dramatic jump in imports,which rose at more than

20% annually from 0.6 million t in the early

1970s to 2.2 million t a decade later. Since 1983,

growth in imports has decelerated as domestic

production has improved, leading to a much more

modest 2.3% annual increase in imports, which

averaged 2.8 million t in the early 1990s. Imports

reached more than 3 million t in 1999, costing

Rice around the world 79

Table 1. Production, consumption, and imports of rice in West Africa, by country, 1999, and average annual

growth rates, 1995-99.


Production a Consumption b Imports b

1999 (t) Growth 1999 (t) Growth 1999 (t) Growth

1995-99 1995-99 1995-99

(%) (%) (%)

Benin 37,198 21.2 110,996 –2.9 129,200 –7.2

Burkina Faso 94,209 2.9 208,103 18.6 142,116 22.9

Cameroon 67,470 17.6 100,945 –7.0 60,003 –16.6

Chad 138,282 15.0 81,029 6.5 2,285 –21.0

Côte d’Ivoire 938,481 -2.7 1,165,806 7.4 429,000 1.5

Gambia, The 31,700 13.7 113,676 9.0 94,265 8.4

Ghana 209,750 1.0 166,107 –11.2 69,131 –9.8

Guinea 750,000 4.4 498,354 –3.7 125,000 –19.0

Guinea Bissau 80,300 –11.9 102,379 –4.3 62,230 1.4

Liberia 196,300 36.7 148,696 24.8 40,700 7.7

Mali 719,600 11.7 537,442 14.4 55,000 4.7

Mauritania 51,878 –0.4 161,243 12.4 122,300 15.0

Niger 60,921 4.5 60,608 –4.1 58,463 10.0

Nigeria 3,277,000 2.9 2,585,224 6.7 687,925 23.1

Senegal 364,000 23.8 653,651 5.8 625,160 9.1

Sierra Leone 247,235 –8.7 423,801 2.0 243,200 0.0

Togo 81,061 24.9 217,911 60.6 238,000 111.1

West Africa 7,345,385 3.8 7,335,971 5.8 3,183,978 6.5


Unmilled paddy rice. b Milled rice.

Source: FAO online database.

more than $800 million in scarce foreign exchange.

Imports of this magnitude represent a

major brake on broader development efforts.

Rice economy liberalization and


The acceleration in per capita rice consumption

since the mid-1990s is due to the liberalization of

rice imports combined with a downward trend of

the price on the world market. Rice trade liberalization

has also opened the door to the importation

of low-quality rice that can be purchased by

the poorest groups.

On the supply side, liberalization has led to a

greater difference in crop yields. While

production efficiency is improving in irrigated

areas where local farmers’ organizations have

taken over previously public institutions, the

disruption of input supply and the unfinished

reform of the rural financial systems have resulted

in a stagnation of yield in other areas. Most of

the increase in irrigated rice production will rely

on improved resource-use efficiency and rehabilitation

of existing irrigation schemes. In the short

term, the largest share of production will be in

rainfed rice-based systems, which require laborsaving

technologies. For the mid term, intensification

in rainfed lowlands through the adoption of

appropriate water management technologies

offers a large and sustainable potential to increase

rice production.

The privatization of the governmentmanaged

rice commodity chain has also allowed

the emergence and fast growth of small-scale

processing units in place of parastatal industrial

mills. This has resulted in decreasing rice

processing costs, thus improving the overall competitiveness

of the local rice vis-à-vis imported

rice. But this change has also led to a degradation

of average local rice quality, which is becoming

quite variable. Consumers now favor lowerquality

imported rice, which does not have the

same organoleptic attributes as local rice, but

which is cleaner and more homogeneous in

appearance, thus requiring less time for

preparation. The future of the West African rice

economy depends highly on the improvement of

supply-to-demand linkages.

Rice as a women’s crop

In many areas of West Africa, rice is produced

primarily by women farmers, thus producing an

important share of their income. Women’s income

tends to benefit children and other vulnerable

groups more than does the income of men.

Despite this fact, past efforts to develop and

transfer new rice technologies have most often

bypassed women farmers. Thus, although rice

80 Rice almanac

Rice in Côte d’Ivoire.

research can be particularly effective in improving

the welfare of rural groups at risk, it needs to

be explicitly structured and focused to deal with

complex gender issues.

Rice, environmental degradation,

and sustainable intensification

In highly populated areas of West Africa, rising

cropping intensity in fragile upland ecosystems

has already begun to degrade the resource base,

with environmental damage and loss in

production potential. Rice has a key role to play

in providing options for sustainable intensification.

Rice is uniquely well adapted to flooded

lowland ecosystems where the soils are least

fragile and best able to support continuous

cultivation. The development of profitable

lowland rice technologies is therefore a central

element in strategies to induce farmers to reduce

pressure on rapidly degraded uplands by shifting

cultivation to lowland ecosystems. Relative to

other cereals, rice also responds more to

improved management and to higher inputs of

nutrients, water control, and labor, and is thus

favored as production systems intensify.

Rice-growing environments

Rice in West Africa is grown in several ecosystems

and in a wide range of production systems.

The humid and subhumid

“continuum” environment

This continuum is composed of several

contiguous ecosystems in which rice can be

grown within the warm subhumid and warm

humid tropics of Africa.

Rainfed upland ecosystem

Rice in this ecosystem is sown on approximately

2.2 million ha, representing 48% of the total rice

area and 29% of regional production. Although

there is large scope for area expansion regionally,

in locations where access to good arable soils is

limited, expansion of upland rice cultivation can

Rice around the world 81

occur only by shifting out of other crops, by

reducing the fallow period, or by exploiting soils

less well suited to rice cultivation. Farm-level

yields are low, averaging about 1 t/ha, and vary as

a function of local soil and rainfall conditions.

Moderate technical potential for increasing yield

exists through improved management. Progressive

farmers applying moderate input levels can

now achieve yields of 2.5 t/ha, and yields of 4

t/ha and greater are commonly achieved on

research stations.

Rainfed lowland/hydromorphic ecosystem

The rainfed lowland ecosystem comprises floodplains

and inland valleys. Overall, rice is grown

on about 1.4 million ha of rainfed lowlands

representing 30% of the total rice area and 36.5%

of regional production. Average yield across the

rainfed lowlands is 2.0 t/ha. In the floodplains,

rice can be grown on residual and water-table

moisture in the broad, flat areas adjacent to rivers

prone to seasonal flooding. Enormous technical

potential exists to expand rice production in

inland-valley lowlands, as currently only about

10–15% of these areas are cultivated. It is

estimated that Sub-Saharan Africa has

approximately 130 million ha of inland-valley

lowlands and their hydromorphic fringes within

which rice can be cultivated. Of this total, West

Africa may have about 20–30 million ha. The

diversity of inland valleys is large. Although

regional yields average around 1.4 t/ha, they vary

according to local soil, landform, and hydrological

conditions. Potential yields in unfavorable

lowlands are around 2.5 t/ha, increasing to more

than 5 t/ha in favorable lowlands.

Lowland irrigated ecosystem

This ecosystem covers about 142,000 ha in West

Africa, representing 3% of the total area and 5.5%

of regional production. The large technical

potential for area expansion is constrained

primarily by high investment costs. Current yields

average around 3.0 t/ha. Progressive farmers

employing moderate to high input management

can obtain yields of 5 t/ha, and yields of 7 t/ha

can be achieved on research stations.

The Sahelian irrigated environment

Irrigated rice in the Sahel forms the second most

important rice-producing environment in West

Africa, covering approximately 345,000 ha (7.5%

of total rice area) and producing 20.5% of

regional production. Irrigation potential is much

greater, estimated at more than 3 million ha along

the Senegal, Niger, Black Volta, Chari, and

Logone rivers. This enormous technical potential

has attracted large public investments: the first

irrigation schemes were constructed in the Sahel

in the 1920s. Until the recent introduction of

privatization policies, the state has played a lead

role in developing and managing irrigated rice

schemes, with over 75% of the areas currently

under parastatal control. The remainder is

managed by a growing and increasingly dynamic

private sector.

Because irrigated rice is an introduced

production system in the Sahel, there are no

traditional varieties or cultural practices upon

which to build. Management skills in water

control and rice cultivation vary widely. Mean

paddy yields are currently about 4.5 t/ha, but vary

widely from as low as 1 t/ha, rising to 4–6 t/ha if

water is available throughout the season, to as

high as 8 t/ha with modern input-responsive

varieties and optimal management. Although ricerice

double cropping is currently practiced on

only about 20% of the total area, by using

varieties with appropriate duration and

adaptation, an annual yield potential of 15 t/ha

can be achieved.

The mangrove swamp rice


Rice is also grown on approximately 147,000 ha

of mangrove swamps, representing 3% of the

total area and producing roughly 4% of the

region’s output. Located on tidal estuaries close to

the ocean, most mangrove swamps experience a

salt-free growing period during the rainy season

when freshwater floods wash the land and displace

tidal flows. As a result, the rice-growing

period is directly related to distance from the

ocean, varying between less than four months in

the nearest estuaries to more than six months in

those more distant. Soils are generally more

fertile than in the other environments since they

benefit from regular deposits of silt left during

annual flooding. However, the soils are also

characterized by high salinity and sulfate acidity.

Lower rainfall during the last two decades has

reduced seasonal flushing substantially, further

accentuating both problems. Although West

Africa has approximately 1 million ha of

82 Rice almanac

Women farmers inspect their crop in The Gambia.

potentially cultivable mangrove swamps, the high

labor costs associated with clearing and

potentially negative environmental effects pose

major constraints to further area expansion.

The deepwater/floating rice


Deepwater and floating rice represent a large but

increasingly marginalized production system for

which area and production figures are generally

poor and vary widely. Estimates of sown area in

the mid-1970s varied from 187,000 to 630,000

ha. It is generally believed that, with the control

of river flooding because of the construction of

dams and with lower rainfall, areas under these

ecosystems have probably declined during the last

20 years. The estimated area under deepwater rice

in West Africa at the end of the 1990s was

373,000 ha, or 8% of the rice-growing area,

producing 5% of production at an average yield

of 1.0 t/ha.

The major zones of production are located

along the Niger valley around Mopti in Mali and

Birnin Kebbi in Nigeria, and in northern Guinea.

Deepwater rice ecosystems can be defined as

those where flooding achieves a depth of from 60

to 100 cm, and floating rice systems as those

where flooding exceeds 100 cm. These

production systems are among the least developed

in West Africa, with very little use of fertilizer or

mechanization and dominated by the use of Oryza

glaberrima and tall traditional O. sativa cultivars.

As a result, yields are among the lowest in the

region, and highly variable across sites and years.

Research to improve these systems has made little


Rice around the world 83

The top 10 rice-producing countries

1. China

2. India

3. Indonesia

4. Bangladesh

5. Vietnam

6. Thailand

7. Myanmar

8. Japan

9. Philippines

10. Brazil


General information

• GNI per capita PPP$, 2000: 3,920

• Internal renewable water resources: 2,800

km 3

• Main food consumed: rice, wheat, meat,

maize, roots, and tubers

Rice consumption, 1999: 90.7 kg milled rice

per person per year

Production season

Planting Harvesting

Early Feb-May Jun-Oct

Intermediate Feb-May Jun-Oct

Late Jun-Jul Oct-Nov

Main season, North Apr-Jun Sep

China is situated between 18° and 54° N

latitude and 73° and 135° E longitude.

Marked by topographical variety and

complexity, China’s landmass is made up of

mountains (33%), plateaus (26%), basins (19%),

plains (12%), and hills (10%).

China lies in four AEZs, all of which are

subtropical and include some temperate areas.

They are AEZ 5, warm arid and semiarid

subtropics with summer rainfall; AEZ 6, warm

subhumid subtropics with summer rainfall; AEZ

7, warm/cool humid subtropics with summer

rainfall; and AEZ 8, cool subtropics with summer

rainfall. Rice is produced primarily in AEZs 6 and


China’s climatic features include a

pronounced monsoon climate with a hot summer

and a cool winter, marked seasonal variations in

precipitation, and a distinctive continental climate

with large annual temperature fluctuations. The

climate types are so varied and complex that high

rainfall, cold waves, and typhoons are all

important climatic phenomena. China can be

divided from the coastal areas to the northwest

interior into four regions according to moisture

regime: (1) the humid region south of the Qinling

Mountains and Huaihe River, comprising 32% of

total land area, (2) the subhumid region including

most of northeastern and central China, 15%, (3)

the semiarid region, 22%, and (4) the arid region,


China is the most populous country in the

world. The 1999 population on the mainland was

nearly 1.3 billion, with about 66% living in rural

areas. Three-fourths of the nation’s population is

concentrated in the northern, northeastern,

86 Rice almanac

eastern, and south-central areas, which make up

only 44% of the nation’s land area. The remaining

one-fourth of the population is dispersed in the

southwestern and northwestern parts. Because of

an active family planning program, including

some restrictions on family size, annual

population growth slowed from 2.6% per annum

in the late 1960s to just 0.9% per annum in the

late 1990s.

Recent developments in the rice sector

Rice is the staple food of China and accounts for

about 35% of total grain production, which was

345 million t in 2000 (converting paddy to its

milled rice equivalent). However, wheat is more

important in some areas, especially in the North.

Although rice is still a large part of people’s diets,

its importance has declined considerably in the

past 15 years. Since 1985, the share of total

calories obtained from rice has fallen from 38%

to 30%. During this same period, the share of

total calories coming from wheat has declined

only slightly, from about 22% to 19%. In terms of

protein, rice and wheat each accounted for

slightly more than one-fourth of total protein

intake in the late 1980s, but during the 1990s this

share declined sharply, and it now stands at

slightly less than one-fifth for each cereal.

China is the world’s largest rice producer,

accounting for 32–35% of total world production

(India has a larger rice area harvested, but lower

per hectare yields). Except for Japan and the

Republic of Korea, rice yields in China are the

highest in Asia, due in part to favorable growing

conditions. Rice area harvested has declined from

its peak of 37 million hectares in the mid-1970s

to just over 30 million ha today. The decline in

area has been due to both economic reforms that

reduced government requirements to grow rice

and economic development that increased the

opportunity cost of land. In recent years, much of

the fall in rice area has occurred in coastal

provinces such as Guangdong and Zhejiang.

Hunan is the largest rice producing province, and

most rice production is in the Yangtze River

Valley (or further south) where ample supplies of

water are available. However, rice production in

northern China has increased substantially in

recent years, with its share of national production

nearly doubling from 7.6% in 1989 to 13.3% in

1999. Much of this increase has come in

Heilongjiang and the other two northeastern

provinces of Jilin and Liaoning, but production

has also expanded noticeably in Henan and


China regularly imports and exports rice each

year. Imports exceeded exports in 1995 and 1996,

but China has been a net exporter since then. In

1998 and 1999, it was the world’s fourth largest

rice exporter (in gross terms, not net), and its

exports helped to stabilize world market rice

prices in the face of a strong El Niño that severely

disrupted production in Indonesia and the


Rice environments

More than 90% of the rice area in China is

irrigated, with only relatively small areas being

cultivated under rainfed conditions. However,

rice-growing conditions vary because of

topography and weather. In southeastern China,

high temperature and adequate rainfall make an

ideal environment for rice during a long growth

period, and many areas grow two crops of rice per

year. In the Yangtze River Valley, much of the

land is planted to a rice-wheat rotation. In

northeastern China, low temperature, a short

growth period, little rainfall, and lack of water

limit the rice area. The varieties grown in this

area are typically japonica and are considered to

be of higher quality than rice grown in other

areas. There are some scattered rice areas in arid

and semiarid regions of northwestern China.

Production constraints

Total area harvested to all crops continues to

increase in China. Area harvested to rice has

declined during the past 25 years, however,

because of crop diversification. (Rice formerly

accounted for 26% of all crop area harvested in

the mid-1970s, but more recently the share is just

20%.) At the same time, population continues to

grow by about 13 million people per year. Until

per capita rice consumption begins to decline

because of rising wealth accompanied by dietary

diversification (as has happened in Japan, the

Republic of Korea, Malaysia, and Thailand), rice

yields will need to increase to meet consumption

demand without resort to imports.

Water shortages in the north are another

important production constraint. Although

northern China has only 24% of the nation’s

water resources, it contains more than 65% of

China’s cultivated land. While water shortages

Rice around the world 87

New rice plant type in Yunnan Province.

constrain production in some areas, flooding is

also a problem. Land salinization and soil erosion

also pose challenges for continued development.

Although the population is still growing,

increased labor demand in urban areas is drawing

many people out of agricultural production and

hurting yields. As a result, labor-saving

technologies such as direct seeding (or seedling

throwing) are becoming more common. Future

trade liberalization under the World Trade

Organization may also affect grain production,

especially for wheat and maize, because domestic

prices for these grains are substantially above

world prices. For rice, however, domestic prices

are approximately equal to world prices, and no

large influx of imports is anticipated.

Production opportunities

Chinese scientists recently became the first in the

world to prepare a draft sequence of the genome

for the indica race of rice. Indica rice is by far the

most widely planted in Asia, and this achievement

has the potential to create many benefits for Asian

producers and consumers of rice.

In seeking to alleviate the main constraints of

land and water, Chinese scientists have also made

substantial progress in improving yields and

water productivity. China has developed the most

successful varieties of hybrid rice in the world,

and more than one-third of total rice area is

currently planted to hybrids. More recently,

scientists have developed irrigation techniques for

rice that reduce water consumption by allowing

intermittent drying of the paddy field, without

sacrificing grain yields. The successful adaptation

of aerobic rice (rice that is grown as an upland

crop but still exhibits a substantial response to

nitrogen fertilizer) to new areas would also allow

rice to be grown in water-short environments. In

the future, construction of canals from southern to

northern China may also help to alleviate water

shortages in the Yellow River Basin.

In other fields, there is also potential for

improved fertilization strategies that increase

nitrogen-use efficiency by improving splitting of

nitrogen and reducing levels of nitrogen

application. Opportunities also exist for reducing

pesticide applications to improve farmer health

and the quality of drinking-water supplies.

Since 1980, China and IRRI have cooperated

on several research projects of mutual concern

such as the exchange of rice germplasm to

strengthen breeding programs; hybrid rice

research to exploit heterosis in rice; shuttle

breeding to speed the development of rice

varieties with high yield potential, good quality,

multiple resistance to insects and diseases, and

wide adaptability; and natural resource

management studies to improve fertilizer- and

water-use efficiencies.

88 Rice almanac



Index (1966 = 100)



Calorie share

Protein share












1966 1971 1976 1981 1986 1991 1996 1999

Share of calories and protein from rice, 1966-99


1966 1971 1976 1981 1986 1991 1996 2000

Indices of rice production, area, and yield, 1966-2000








1966 1971 1976 1981 1986 1991 1996 1999

Per capita production (paddy terms), 1966-99















1966 1971 1976 1981 1986 1991 1996 1999

Net trade status, 1966-99

Basic statistics, China

1985 1990 1995 1998 1999 2000


Area harvested (ha) 32,633,684 33,518,971 31,107,479 31,571,500 31,637,100 30,503,100

Yield (t/ha) 5.2 5.7 6.0 6.4 6.3 6.2

Production (t) 171,318,871 191,614,680 187,297,968 200,571,557 200,403,308 190,168,300

Rice imports (t) na na na 246,892 172,106 na

Paddy imports (t) 0 465 173 229 258 na

Rice exports (t) 1,045,848 405,381 235,934 3,791,615 2,819,010 na

Paddy exports (t) 0 203 1,308 1,889 4,953 na


Population, total (×10 3 ) 1,075,936 1,161,382 1,227,170 1,262,817 1,274,107 na

Population, agriculture (×10 3 ) 783,923 834,688 850,299 854,536 855,167 na

Agricultural area (×10 3 ha) 495,897 531,398 534,701 535,566 na na

Irrigated agricultural area (×10 3 ha) 44,584 47,967 49,859 52,582 na na

Total fertilizer consumption (t) 16,851,600 27,027,408 35,181,200 35,077,600 na na

Tractors used in agric. (no.) 861,364 824,113 685,202 704,070 na na

Source: FAOSTAT online database.

Rice around the world 89


General information

• GNI per capita PPP$, 2000: 2,340

• Internal renewable water resources: 1,850

km 3

• Incoming water flow: 235 km 3

• Main food consumed: rice, wheat, sugar and

honey, millet and sorghum, oil and fat

Rice consumption, 1999: 74.2 kg milled rice

per person per year

Production season

Planting Harvesting

Kharif early Mar-May Jun-Oct

Kharif medium Jun-Oct Nov-Feb

Rabi Nov-Feb Mar-Jun

India extends between 8°4′ and 37°6′ N

latitude and 68°7′ and 97°25′ E longitude. It

measures about 3,214 km from north to south

between the extreme latitudes and about 2,933 km

from east to west between the extreme longitudes.

It has a land frontier of about 15,200 km. The

mainland comprises four regions: the great

mountain zone, plains of the Ganges and the

Indus rivers, the desert region, and the southern

peninsula. On its northern frontiers, India is

bounded by the Great Himalayas, which are three

almost parallel ranges interspersed with large

plateaus and valleys, such as the Kashmir and

Kullu valleys, that are very fertile.

India lies in five agroecological zones: AEZ

1, characterized by warm and semiarid tropics;

AEZ 2, warm subhumid tropics; AEZ 5, warm

arid and semiarid subtropics with summer

rainfall; AEZ 6, warm subhumid tropics with

summer rainfall; and AEZ 8, cool subtropics with

summer rainfall. Most rice is grown in AEZs 1, 2,

and 6.

The climate of India can be described as

tropical monsoon type. There are four seasons:

winter (December-February), summer (March-

May), rainy southwestern monsoon (June-

September), and postmonsoon, also known as

northeastern monsoon in the southern peninsula

(October-November). The beginning of winter

and summer periods differs in different regions.

Four broad climatic regions are identified

based on rainfall. The whole of Assam and the

west coast of India lying at the foot of the

Western Ghats and extending from the north of

Mumbai (earlier Bombay) to Thiruvanthapuram

(earlier Trivandrum) are areas of high rainfall.

90 Rice almanac

The Rajasthan desert extending westward to

Gilgit is a region of low precipitation. In between

are two areas of moderately high and low rainfall.

The area of high rainfall is a broad belt in the part

of the peninsula merging northward with the

Indian plains and southward with the coastal

plains. The low rainfall area is a belt extending

from the Punjab plains across the Vindhya

mountains into the western part of the Deccan

region, widening considerably in the Mysore


India is the world’s second most populous

nation, with a population in 2000 of 1,014 million

growing at 1.7% per year. The rural population in

2000 was 726 million.

Recent developments in the rice sector

Agriculture is the backbone of India’s economy,

providing direct employment to about 67% of the

working people in the country. It forms the basis

of many premier industries of India, including the

textile, jute, and sugar industries. Agriculture

contributes about 29% to GDP; one-fourth of

India’s exports are agricultural products.

Rice is the staple food of 65% of the total

population in India. It constitutes about 52% of

the total food grain production and 55% of total

cereal production. Food grains consist of cereals

such as rice, wheat, sorghum, pearl millet, and

maize as well as pulses. Food crops grow on

nearly 70% of the gross sown area. Important

commercial crops are cotton, jute, sugarcane, and


Rough rice production reached 134 million t

in 2000 from 112 million t in 1990, growing at

1.9% annually. The growth rate has slowed down

significantly from 3.4% per year during the

1980s, mainly from the sluggish performance in

the progressive states such as Punjab, Andhra

Pradesh, Tamil Nadu, and Haryana, as many

districts in these states are approaching the

economically optimum yield with the available


The rough rice yield has increased from 2.61

t/ha in 1990 to 3.01 t/ha in 2000, an annual

growth of 1.4%. In Punjab and Tamil Nadu,

where almost the entire rice land is irrigated,

yield has reached 5.26 t/ha and 5.38 t/ha (1998),

respectively. Yield fluctuates widely in Bihar and

Orissa, states that suffer from drought and floods

often in the same year, making rice cultivation a

highly risky economic activity.

Adoption of modern technology

Since 1965, India has released about 640

improved rice varieties: 54% of them for irrigated

areas, 27% for the rainfed lowland, and 19% for

upland areas. The coverage of modern highyielding

rice varieties reached 78% of the rice

harvested area by 1999. The rate of adoption

varies from 67% in Assam in the northeast to

more than 90% in Andhra Pradesh, Tamil Nadu,

and Kerala in the south. Since a large area in the

irrigated states of Punjab and Haryana in the

northwest is allocated for the production of highquality

basmati rice, traditional varieties account

for a significant portion of rice land in these


Swarna (MTU 7029), a derivative of

Mahsuri, is the most popular improved rice

variety that is grown in a large number of states.

In 1999, it was grown on about 12% of India’s

rice land. The other popular varieties are Vijeta

(MTU 1001), Samba Mahsuri (BPT 5204),

Mahsuri, Lalat, IR64, and IR36.

Data on fertilizer sales show a large regional

variation in the use of nutrients. NPK use varies

from less than 50 kg/ha in Assam, Orissa, and

Madhya Pradesh (mostly rainfed areas) to more

than 140 kg/ha in Punjab, Andhra Pradesh, and

Haryana (irrigated land). A report on the cost of

cultivation of principal crops in 2000 notes a

heavy use of pesticides in rice cultivation in

Punjab and Andhra Pradesh but very little in other

states. Mechanization of agricultural operations is

prevalent in Punjab and Haryana and is gaining

ground in Andhra Pradesh, western Uttar Pradesh,

and West Bengal, but is almost absent in other


External trade

In the 1960s, India imported 0.7 to 1.0 million t

of rice annually to meet the deficit in domestic

demand. India became self-sufficient in rice in

1977 with imports of small amounts in years of

crop failures. The latest large imports were 0.5

million t in 1984, 0.7 million t in 1988, and 0.47

million t in 1989. Since then, imports of rice have

been limited to below 100,000 t.

India exports a small amount of high-quality

basmati (aromatic) rice on a regular basis.

Exports of rice jumped from 0.9 million t in 1994

to 4.9 million t in 1995 in response to the large

increase in demand in the world market.

However, India could not sustain exports at that

Rice around the world 91

level because of the low quality of indica rice, of

which a substantial surplus is produced in Punjab

and Andhra Pradesh. Although there is a large

unmet demand for staple food grains in the

poverty-stricken states of eastern India because of

a lack of purchasing capacity of low-income

households, the disposal of the surplus rice

procured by the government has become a major

concern for India.

Rice environments

Rice environments in India are extremely diverse.

India has the largest area under rice in the world.

Of the 45 million ha of harvested rice area, about

28% are rainfed lowland, 46% irrigated, 12%

rainfed upland, and 14% flood-prone. In some

traditional wheat-growing states, such as Punjab,

Haryana, and Uttar Pradesh, rice production has

increased substantially since the late 1960s with

the introduction of modern high-yielding rice

varieties that induced farmers to undertake

commercial cultivation of rice. In Punjab, for

example, rice production increased from 0.9 to

13.1 million t, and in Uttar Pradesh from 4.4 to

19.4 million t from 1968 to 1999. This rapid

expansion was possible because of the favorable

irrigation infrastructure.

Production constraints

Since the major portion (55%) of the area under

rice in India is rainfed, production is strongly tied

to the distribution of rainfall. In some states,

erratic rainfall leads to drought during the

vegetative period, but later the crop may be

damaged by submergence caused by high rainfall.

In the eastern states, damage from flash floods is

quite high.

Other constraints relate to the land and soil.

Soil acidity is a problem in southern and eastern

India, whereas, in northern India, soil salinity and

alkalinity are the problem. Low soil fertility and P

and Zn deficiency are widespread.

Nearly all of the rainfed area suffers from a

lack of infrastructure. Moreover, most farmers

cannot afford the inputs necessary for full

exploitation of the yield potential of modern

varieties. Crop residues are used as livestock feed

and for thatching of roofs of houses; animal dung

is used for fuel, and is not available to

compensate for the loss of nutrients in the

cultivation of modern varieties.

Stem borers, brown planthopper, gundhi bug,

leaffolders, green leafhopper, and gall midge are

major insect pests causing large yield losses.

Bacterial blight, blast, sheath blight, and brown

spot are important diseases. With increases in

wage rates, weeds are becoming a major factor

constraining productivity and profitability in rice


Production opportunities

Much of India’s agricultural growth, particularly

in major cereals, can be traced to an agricultural

strategy adopted in the late 1960s. The strategy


• provision of a package of inputs consisting

of short-duration, high-yielding modern

varieties, fertilizers, and improved

agricultural practices in areas of assured

water supply;

• supply of credit from public institutions to

finance working capital needs of farmers;


• declaration of a minimum price before

planting at which surplus grains are to be

procured by the government.

To extend the production package to less

favored areas in order to achieve more balanced

regional growth, agroclimatic zonal planning is

applied. India has been divided into 21 agroclimatic

regions based on homogeneity in rainfall,

temperature, soil, topography, and water

resources. Rice research priorities have shifted

from the irrigated ecosystem in the northwest and

southern region to the predominantly rainfed

ecosystem in eastern and northeastern India.

Strategic research to increase the productivity of

rice is being done in collaboration with the

International Fund for Agricultural Development

and the International Rice Research Institute in

six states in eastern India that account for twothirds

of the total rice area. The Rice-Wheat

Consortium for the Indo-Gangetic Plains is

studying the problem of sustainability of high

yields in rice and wheat by examining systemlevel


92 Rice almanac



Index (1966 = 100)



Calorie share

Protein share












1966 1971 1976 1981 1986 1991 1996 1999

Share of calories and protein from rice, 1966-99


1966 1971 1976 1981 1986 1991 1996 2000

Indices of rice production, area, and yield, 1966-2000








1966 1971 1976 1981 1986 1991 1996 1999

Per capita production (paddy terms), 1966-99















1966 1971 1976 1981 1986 1991 1996 1999

Net trade status, 1966-99

Basic statistics, India

1985 1990 1995 1998 1999 2000


Area harvested (ha) 41,137,200 42,686,608 42,800,000 44,598,000 44,607,000 44,600,000

Yield (t/ha) 2.3 2.6 2.7 2.9 3.0 3.0

Production (t) 95,817,696 111,517,408 115,440,000 128,928,000 132,300,000 134,150,000

Rice imports (t) 61,100 66,038 526,635 50,094 na

Paddy imports (t) 0 0 80 3 3 na

Rice exports (t) 315,070 505,027 4,913,156 4,962,941 2,571,000 na

Paddy exports (t) 1,020 7 2,444 1,878 0 na


Population, total (×10 3 ) 767,842 850,785 933,665 982,223 998,056 1,014,000

Population, agriculture (×10 3) 10,475,832 506,548 534,245 548,794 553,227 na

Agricultural area (×10 3 ha) 180,949 181,040 180,780 180,600 na na

Irrigated agricultural area (×10 3 ha) 41,779 45,144 53,000 59,000 na na

Total fertilizer consumption (t) 8,504,300 12,584,000 13,876,100 16,797,500 na na

Tractors used in agric. (no.) 607,773 988,070 1,354,864 1,550,000 na na

Source: FAOSTAT online database.

Rice around the world 93


General information

• GNI per capita PPP$, 2000: 2,830

• Internal renewable water resources: 2,530

km 3

• Main food consumed: rice, oil and fat, nuts,

roots and tubers, maize

Rice consumption, 1999: 154 kg milled rice

per person per year

Production season

Planting Harvesting

Main season, Java and Oct-Mar Feb-Jun

South Sumatra

Main season, Sulawesi May-Jun Aug-Oct

Main season, Sumatra Jul-Sep Nov-Dec

The Indonesian archipelago extends from 6°

N to 11° S latitude and from 95° to 141° E

longitude or about 2,000 km from north to

south and 5,000 km from east to west. There are

more than 13,000 islands, including five of the

world’s largest: Sumatra, Kalimantan (Indonesian

part of Borneo), Irian Jaya (western New

Guinea), Sulawesi (Celebes), and Java.

Indonesia lies within AEZ 3, characterized as

the warm humid tropics. Most of Indonesia has a

moist tropical climate, with abundant rain and

high temperatures. Annual rainfall ranges from

1,000 to more than 5,000 mm per year, with more

than 90% of the country receiving average

rainfall of more than 1,500 mm. December

through March are the months with the highest


Indonesia is the world’s fourth most

populous country, with about 215 million people

as of 2001. Because of rapid economic growth

and an active family planning program,

population growth has declined from 2.4% per

annum during the late 1960s and early 1970s to

1.5% recently, and the United Nations forecasts

this rate to decline to less than 1% by 2015. The

mean population density is 111/km 2 , but, on Java,

where nearly 60% of the people reside, the

population density is approximately 980/km 2 . The

share of the population in urban areas has grown

to 40%, with the remainder in rural areas. About

half of the economically active population is in

agriculture, although many of these people derive

a substantial share of their income from nonagricultural

activities. The incidence of

94 Rice almanac

malnutrition among children age 2–5 (as

measured by weight for age) is estimated at 34%.

Recent developments in the rice sector

The agricultural sector (including forestry and

fisheries) contributed approximately one-sixth of

GDP in 2000, with rice production responsible for

about one-fourth of this contribution. Rice

constitutes nearly 40% of total crop area

harvested and is the country’s staple food,

accounting for slightly more than half of caloric

intake and nearly half of protein intake. Rice

accounts for 20% of total expenditures for the

poorest quarter of the urban population. Even in

rural areas, many poor people are net consumers

of rice, since 45% of rural households on Java do

not own any land and another 20% own less than

0.25 ha. In the 1970s and early 1980s, Indonesia

was the world’s largest rice importer, often

importing one-fourth of total supplies on the

world market. From 1967 to 1986, however, total

rice production tripled, probably the most

extraordinary growth rate of staple food

production in human history, and self-sufficiency

was achieved by the mid-1980s. This rapid

production growth was achieved through the

adoption of modern high-yielding varieties and

fertilizers by farmers. Adoption of these varieties

was greatly facilitated by government programs

such as fertilizer subsidies and rice price

stabilization around the long-term trend of world

prices. Large investments in rural infrastructure

such as irrigation, roads, and schools also played

a critical role.

While per hectare yields more than doubled

from the mid-1960s to the mid-1980s, the

national average yield today is no greater than it

was ten years ago. This stagnation has been the

primary factor behind Indonesia’s return as the

largest importer on the world market in the

second half of the 1990s. Despite continued

urbanization, rice harvested area increased

steadily during the past decade, from about 10.5

million hectares in 1990 to nearly 12 million ha in


Rice policy has changed substantially in the

aftermath of the Southeast Asian financial crisis

that led to the resignation of President Suharto in

1998. A substantial increase in rice prices in late

1998 led to significant increases in poverty, and

this precipitated shifts in policy. While the

national logistics agency Bulog formerly had

monopoly control over all rice import and export

decisions, adoption of an International Monetary

Fund stabilization program led to the entry of

private-sector traders, who are currently allowed

to make import decisions subject only to a tariff.

Bulog’s successful defense of farm-gate floor

prices for nearly 30 years also ended because of

political and institutional constraints. Recently, all

subsidies on fertilizer were eliminated.

Rice environments

As of the mid-1990s, 54% of the rice area in

Indonesia was irrigated, with 35% rainfed

lowland, and 11% upland. Nearly all of the

irrigated area can be planted to two or more crops

of rice per year, and much of the rainfed area has

favorable growing conditions. Most irrigated

lowland rice areas are located in floodplains.

However, they can also be found on mountainsides

wherever there is water. Rainfed lands are

on both floodplains and undulating landscapes.

Uplands are mostly on undulating landscapes.

Current estimates are that about 80% of rice land

is planted to modern varieties. On Java, most rice

is transplanted. Labor use in rice production is

relatively high, typically exceeding 200 persondays

per hectare per crop.

Production constraints

In irrigated and favorable rainfed lowlands,

especially on Java, the relatively heavy

application of nitrogenous fertilizers makes

nutrient imbalance a serious problem. Indonesia

is also particularly vulnerable to the vagaries of

the El Niño Southern Oscillation (ENSO)

phenomenon. In years when surface water

temperatures rise substantially in the western

Pacific Ocean, signaling an El Niño event, rice

production suffers a serious shortfall, with most

of the effects coming from a reduction in rice area

planted (as opposed to lower yields). The

reduction in area occurs even in systems that are

usually irrigated, as lower rainfall leads to a

reduced availability of irrigation water.

In upland rice areas, erosion is a serious

problem because on steep slopes the fields are

neither bunded nor terraced. This can cause

serious sedimentation problems in lowland

irrigation systems. Alley cropping as well as

terracing are being introduced in some areas, but

these cultural practices have not yet been widely

adopted by farmers. Upland soils are also more

weathered and leached, leading to problems of Al

toxicity and P nutrient deficiencies that combine

Rice around the world 95

Weighing the rice harvest in West Java.

to reduce yields. Soil acidity is serious in tidal

swamps because of acid-sulfate soils. That is

accompanied by Fe toxicity as well as some

deficiencies of P and micronutrients.

Production opportunities

Indonesia has developed a cadre of researchers

capable of undertaking rice research and

collaborating with colleagues in other countries.

The Research Institute for Rice (RIR), located in

Sukamandi, West Java, is the main institute

conducting biophysical rice research. Some trials

and assessments on rice are also conducted by the

regional institute of the Assessment Institute for

Agricultural Technology (AIAT) at the provincial

level. The Center for Agro-Socio-Economic

Research (CASER), located in Bogor, has a long

tradition of conducting socioeconomic research on

rice and the agricultural sector more broadly.

Future research efforts will need to focus on

several areas:

• achieving higher and sustainable rice yields

through integrated crop and resource


• breeding of varieties with higher yield

(Indonesia is a member of the hybrid rice

network) and actively testing and

developing the new plant type

• further breeding of varieties resistant to

pests and diseases using marker-aided

selection and other techniques

• development of varieties tolerant of

drought and soil toxicities

• development of varieties and other

strategies to stabilize yields

• development of improved nutrient

management strategies

• crop diversification

96 Rice almanac



Index (1966 = 100)



Calorie share

Protein share












1966 1971 1976 1981 1986 1991 1996 1999

Share of calories and protein from rice, 1966-99


1966 1971 1976 1981 1986 1991 1996 2000

Indices of rice production, area, and yield, 1966-2000








1966 1971 1976 1981 1986 1991 1996 1999

Per capita production (paddy terms), 1966-99















1966 1971 1976 1981 1986 1991 1996 1999

Net trade status, 1966-99

Basic statistics, Indonesia

1985 1990 1995 1998 1999 2000


Area harvested (ha) 9,902,293 10,502,357 11,438,760 11,716,499 11,963,204 11,523,068

Yield (t/ha) 3.9 4.3 4.3 4.2 4.3 4.4

Production (t) 39,032,944 45,178,752 49,744,140 49,199,844 50,866,388 51,000,000

Rice imports (t) 33,853 49,577 3,157,700 1,894,958 4,748,060 na

Paddy imports (t) 0 0 1,051 461 9,539 na

Rice exports (t) 258,712 1,911 5 1,981 2,701 na

Paddy exports (t) 381,096 100 0 57 1 na


Population, total (×10 3 ) 167,332 182,812 197,464 206,338 209,255 na

Population, agriculture (×10 3 ) 87,419 93,085 93,591 93,679 93,651 na

Agricultural area (×10 3 ha) 39,350 45,083 41,980 42,164 na na

Irrigated agricultural area (×10 3 ha) 4,300 4,410 4,687 4,815 na na

Total fertilizer consumption (t) 1,971,800 2,387,000 2,529,200 2,772,900 na na

Tractors used in agric. (no.) 12,033 27,955 59,991 70,000 na na

Source: FAOSTAT online database.

Rice around the world 97


General information

• GNI per capita PPP$, 2000: 1,590

• Internal renewable water resources: 1,357

km 3

• Incoming water flow: 1,000 km 3

• Main food consumed: rice, wheat, oil and fat,

sugar and honey, pulses

Rice consumption, 1999: 168.2 kg milled

rice per person per year

Production season

Planting Harvesting

Aus Apr-May Jul-Aug

Aman Apr-May Nov-Dec

Boro Dec-Feb Apr-May

Bangladesh lies in the northeastern part of

South Asia between 20° and 26° N

latitude and between 88° and 92° E

longitude. The country is bounded by India on the

west, north, and northeast; by Myanmar on the

southeast; and by the Bay of Bengal on the south.

Except for the hilly regions in the southeast

and some in the northeast, and patches of

highlands in the central and northwest regions,

Bangladesh for the most part consists of low, flat,

fertile land. About 230 rivers and their tributaries,

with a total length of about 24,140 km, flow

across the country down to the Bay of Bengal.

The alluvial soil is continuously enriched by

heavy silt deposited by the rivers through

frequent flooding during the rainy season.

Bangladesh is in AEZ 3, characterized as

warm humid tropics, with a length of growing

period >230 d for most parts of the country. The

country enjoys a subtropical monsoon climate.

Summer, monsoon, and winter are the most

prominent of six distinct seasons. Winter, which

is pleasant, extends from November to February,

with minimum temperature ranging from 7 to 13

°C; in summer, maximum temperature ranges

from 24 to 41 °C.

The monsoon starts in June and lasts until

October. This period accounts for 80% of the total

annual rainfall, which varies from 1,200 to 2,500

mm. Maximum rainfall is recorded in the coastal

areas and in the northern Sylhet and Mymensing

districts, adjacent to Assam and Meghalaya,

India. Minimum rainfall is observed in the

districts of Jessore, Kushtia, and Rajshahi in the

western parts of the country.

98 Rice almanac

Recent developments in the rice sector

Nearly 80% of the land area of the country has

been brought under crop cultivation. Only 15% of

the land area is under forests. In 1999-2000,

nearly 50% of the net cropped land was double

cropped, and 13% triple cropped. The cropping

intensity was 175% in the mid-1990s. Cropping

intensity is low, however, in the salinity-affected

coastal areas and in the flood-prone depressed


Agriculture, the main occupation of the

people, employs 63% of the active labor force. It

contributed 30% to GDP in 2000, 57% of which

came from crop production. Rice accounts for

about 77% of total cropped area and two-thirds of

the value added in crop production. The emphasis

of government policy and research has been on

achieving food grain production self-sufficiency

with positive support for the distribution of

modern agricultural inputs such as chemical

fertilizers and irrigation water. This policy

support and major achievements of the publicsector

research and extension agencies have

enabled the country to achieve a record 5% per

year growth in cereal production from 1996 to

2000. The current development strategy focuses

on agricultural and crop diversification through

reallocation of resources away from the

production of rice, to be achieved through a

continuous increase in the productivity of land

and labor, and timely supply of high-quality seeds

and fertilizer.

Rice environments

The major rice ecosystems are upland (directseeded

premonsoon aus), irrigated (mainly dryseason

boro), rainfed lowland (mainly monsoonseason

transplanted aman, 0–50 cm), mediumdeep

stagnant water (50–100 cm), deepwater

(>100 cm), tidal saline, and tidal nonsaline.

The rice area has remained almost constant

since the independence of Bangladesh in 1971,

but there has been a major shift in rice cultivation.

Over the last three decades, the area under

high-yielding boro rice has increased from 0.8 to

3.4 million ha, at the expense of the very lowyielding

and risky deepwater aman and upland

aus rice crops. Over this period, the area under

aus rice has declined from 3.4 to 1.3 million ha

and that of deepwater aman rice from 2.1 to 0.7

million ha. However, aman rice still covers 5.7

million ha. Recently, some aus rice land has been

diverted for the cultivation of high-value

vegetable and fruit crops.

Modern varieties (MVs) make up about 95%

of boro (irrigated) rice. Transplanted aman is

about 60% MVs, aus about 40%. Deepwater rice

is exclusively local varieties. The reallocation of

Bangladeshi farmer heads for his field.

Rice around the world 99

land from traditional varieties to MVs is the main

source of growth in rice production and yield. The

present average rice yield of about 3.4 t/ha

increased at 2.2%/yr from 1990 to 2000. Rice

production reached 36 million t in 2000, an

increase of 2.5%/yr over the last decade, and

5%/yr over the last five years in spite of a

devastating flood in 1998.

Production constraints

Sustainability is always a problem wherever

intensified cropping systems are practiced and

crop residues are removed for fuel and feed. Cow

dung, a traditional source of fertilizer, is being

diverted to meet an acute shortage of fuel in rural

areas. The use of chemical fertilizers has

increased rapidly along with the spread of MVs,

from 11 kg NPK/ha in 1970 to 110 kg NPK/ha in

2000. With the removal of fertilizer subsidies in

the late 1980s, fertilizer use became unbalanced,

with too much use of N and too little P, in

response to an unfavorable trend in the relative

price of P and K, which are mostly imported.

Drought is a frequent problem, but

supplemental irrigation during the late monsoon

could alleviate it. Subsurface groundwater is

available almost everywhere in the country.

Irrigation by small-scale tube wells and low-lift

pumps began in the late 1970s when government

control over the procurement and distribution of

modern agricultural inputs was abolished. The

spread of tube wells has increased more rapidly

since the late 1980s when the importation of

agricultural machinery was liberalized. In 1999,

rice constituted nearly 80% of the total irrigated

area; 70% is irrigated with shallow tube wells and

power pumps owned and operated by farmers.

Overexploitation of groundwater is becoming an

environmental concern with adverse effects on

the supply of drinking water; there are suspected

links to arsenic-contaminated water.

Flooding occurs annually, but causes serious

damage only about once every 10 years. Normal

flooding is simply a part of the ecosystem and

helps to maintain soil quality. The flood-prone

areas are ideally suited for boro rice, as water is

available during the dry season and the cost of

irrigation is low.

Soils in coastal areas are affected by salinity.

Most soils are low in organic matter (many less

than 0.5%) and consequently low in N. Zinc and

S deficiencies are common; replacement amounts

of P and K are insufficient.

Marketing infrastructure is adequate for rice

but inadequate for other agricultural commodities,

especially perishables. The prices of both rice and

nonrice crops fluctuate seasonally because of the

lack of access to international markets and

occasional good or poor harvests that affect the

demand-supply balance within the economy. The

price of rice is now too low to provide incentives

to farmers to sustain growth in production. When

food grain production approaches self-sufficiency,

farm-gate prices of rice go down quickly. A

policy to move stored grain routinely into market

channels and replace it with fresh stocks is

needed to stabilize rice prices.

The main challenge to food self-sufficiency

in Bangladesh is sustainability of production in

view of the many man-made, biotic, and abiotic

constraints. Population is a bigger problem than

food production inasmuch as food production is

basically keeping pace with population growth.

Population density is 900 persons/km 2 , one of the

highest in the world. Bangladesh has made

notable progress in population control since the

late 1980s. The 2001 population census reports a

growth rate of 1.6%/yr from 1991 to 2001

compared with 2.4%/yr for 1981-91.

Production opportunities

Rice research and development are effective, but

could be streamlined with more effective linkages

between research and extension.

Among the measures that would help

stabilize rice supply and encourage agricultural

growth are the spread of shorter-duration MVs to

intensify cropping; further development of

drainage and irrigation facilities; development of

varieties tolerant of salinity, drought, and

submergence to raise productivity in coastal and

flood-prone areas; and reducing the yield gap in

irrigated areas with the spread of knowledgeintensive

crop and natural resource management


100 Rice almanac



Index (1966 = 100)











Calorie share

Protein share




1966 1971 1976 1981 1986 1991 1996 1999

Share of calories and protein from rice, 1966-99


1966 1971 1976 1981 1986 1991 1996 2000

Indices of rice production, area, and yield, 1966-2000








1966 1971 1976 1981 1986 1991 1996 1999

Per capita production (paddy terms), 1966-99















1966 1971 1976 1981 1986 1991 1996 1999

Net trade status, 1966-99

Basic statistics, Bangladesh

1985 1990 1995 1998 1999 2000


Area harvested (ha) 10,398,170 10,435,340 9,951,700 10,115,630 10,708,000 10,700,000

Yield (t/ha) 2.2 2.6 2.7 2.9 3.2 3.3

Production (t) 22,556,288 26,777,904 26,398,000 29,708,000 34,426,800 35,820,800

Rice imports (t) 677,323 380,062 995,946 1,127,208 2,215,322 na

Paddy imports (t) 0 0 579,601 168,472 0 na

Rice exports (t) 0 0 58 105 170 na

Paddy exports (t)



Population, total (×10 3 ) 99,373 109,465 118,616 124,774 126,947 na

Population, agriculture (×10 3 ) 68,496 71,460 71,868 71,985 72,001 na

Agricultural area (×10 3 ha) 9,735 10,037 8,748 8,932 na na

Irrigated agricultural area (×10 3 ha) 2,073 2,936 3,429 3,844 na na

Total fertilizer consumption (t) 540,682 933,022 1,194,097 1,171,000 na na

Tractors used in agric. (no.) 4,900 5,200 5,300 5,400 na na

Source: FAOSTAT online database.

Rice around the world 101


General information

• GNI per capita PPP$, 2000: 2,000

• Internal renewable water resources: 376 km 3

• Main food consumed: rice, roots and tubers,

meat, sugar and honey, fruits

Rice consumption, 1999: 170.3 kg milled

rice per person per year

Production season

Planting Harvesting

Main season May-Aug Sep-Dec

Winter-spring Dec-Feb Apr-Jun

Summer-autumn Apr-Jun Aug-Sep

Vietnam is located along the eastern margin

of the Indochina peninsula in Southeast

Asia, extending from 8° to 23° N latitude.

It is bounded by Cambodia, Lao PDR, China, and

the South China Sea.

It is in AEZ 3, characterized as warm humid

tropics. Over 30% of the country is forested and

about 17% is cultivated for seasonal crops, with

another 5% under permanent crops. Climate

varies from humid tropical in the southern

lowlands to temperate in the northern highlands.

There are two monsoon seasons: the northeastern

winter monsoon and the southwestern summer

monsoon. Destructive typhoons sometimes

develop over the South China Sea during hot

weather. Mean annual sea level temperatures

decline from 27 °C in the south to 21 °C in the

extreme north.

Mean annual rainfall ranges from 1,300 to

2,300 mm. Rainfall is usually evenly distributed

in June to October or November. In the Mekong

Delta, the summer monsoon brings 5–6 months of

rainfall above 100 mm/mo. October is the wettest

month of the year.

The population of Vietnam was about 79

million in 1999 with an average density of 245/

km 2 . The population grew at 1.7%/yr during the

1990s. Eighty percent of the population is rural

and concentrated in the two rice-growing deltas:

the Red River Delta in the north and the Mekong

River Delta in the south. Total labor force was 42

million, with two-thirds engaged in agriculture.

The agricultural labor force grew by 17% during

the 1990s compared with a 23% growth in total

labor force.

102 Rice almanac

Recent developments in the rice sector

The gross domestic product was estimated at

US$27.2 billion for 1998. Agriculture continues

to play a dominant role, contributing 21% to the

GDP and 30% of total export earnings.

Rice is the single most important crop. It is

cultivated on 4.2 million ha out of 5.7 million ha

of arable land. The planted area for rice increased

from 5.6 million ha in 1980 to 7.7 million ha in

2000. Cropping intensity has reached 183%, the

highest in the world. The rapid increase in rice

area and the intensity of rice cropping have been

made possible by heavy investment in flood

control, drainage, irrigation that turned the floodprone

ecosystem in the Mekong River Delta into

an irrigated ecosystem, and the development of

very short duration rice varieties.

In 1981, Vietnam departed from the

collective agricultural production system by

introducing the group-oriented contract system of

production. That was changed to individual

contracts, beginning in 1986. The average farm

size is very small. The number of farm

households was estimated at 9.5 million in 1994,

with 8.4 million having a size of less than 1 ha.

By official estimates, the average small-farm

household’s share of income from the crops it

harvests has risen from 20% before the 1986

reforms to around 60% in the mid-1990s.

Vietnam achieved an impressive growth in

rice production after the policy reforms in 1986.

Total output increased from 15.1 million t in 1987

to 32.6 million t in 2000, a growth of 6.1%/year.

Much of the growth came from the expansion of

the rice harvested area, as farmers shifted land

from a long-duration single-cropped deepwater

rice to double- and triple-cropped short-duration,

high-yielding modern varieties, particularly in the

south. There has also been an impressive growth

in rice yield, from 2.70 t/ha in 1987 to 4.25 t/ha in

2000, a growth of 3.3%/year.

As a result of the spectacular growth in rice

production, Vietnam has been a major rice

exporter since 1989. Initially, it captured the

international market for low-quality rice, but over

time the milling quality has improved. Exports of

milled rice have continuously increased from 1.4

million t in 1989 to 4.6 million t in 1999. Vietnam

is now the second largest exporter of rice in the

world market, after Thailand.

Rice environments

About 52% of Vietnam’s rice is produced in the

Mekong River Delta and another 18% in the Red

River Delta. The other major rice-growing

regions are the northeast and the north-central

coast. The northern provinces of Vietnam have a

total rice area of 2.5 million ha or about a third of

the total rice planted area. Almost 85% of the

total area is irrigated lowland, 12% is shallow

rainfed, and 4% is intermediate rainfed. The

dominant cropping pattern is spring-summer rice.

The Red River Delta, which is extremely

densely settled and has very small landholdings,

has long been practicing double rice cropping

with highly labor-intensive rice cultivation

methods. The winter and spring season rice crops

cover almost the same area (530,000 ha), with a

yield of 5.2 and 5.7 t/ha, respectively.

The Mekong River Delta has three major

cropping seasons: spring or early season, autumn

or midseason, and winter, the long-duration wetseason

crop. The largest rice area is cropped

during the autumn season (1.95 million ha),

followed by spring (1.45 million ha), and only a

small area is cropped in winter (0.6 million ha).

The rice yield is highest in the spring season (5.3

t/ha), and lowest in the winter season (3.3 t/ha).

Farmers in this region adopt a direct-seeding

method of crop establishment to save labor costs.

Fifty-two percent of the rice in the Mekong River

Delta is grown in irrigated lowlands, with the

remaining 48% grown under rainfed conditions.

Soils in the Mekong River Delta are highly

variable, but alluvial, acid-sulfate, and saline

soils predominate. Acid-sulfate soils cover some

1.6 million ha, or 40% of the delta, mainly in the

Plain of Reeds, Long Xuyen Quadrangle, and Ca

Mau Peninsula. The soil is rich in humus and

total N, but low in P. In addition, Al and Fe

toxicities limit yield.

Alluvial soils, prevalent in 30% of the

Mekong River Delta, are concentrated along the

banks of the Tien (Mekong) and Hau (Bassac)

rivers. This is the best soil in the delta, with

humus content of 2%, total N of 0.1–0.25%, and

medium P and K. Two to three crops can be

grown on these soils each year.

Coastal saline soils occupy about 20% of the

total area. The soils are rich in humus, N, and

clay (55–60%), but have a high salt content.

Rice around the world 103

Rice harvest transport on the Mekong River system.

Production constraints

The major constraints are flooding at the end of

the rainy season and drought in the dry season.

Small farm size, a problem that is expected

to increase even further because of population

pressure, is a major constraint. The low and

declining price of rice with the increase in rice

harvest provides inadequate income for the

sustenance of farming families. The low

profitability in rice farming is a major

disincentive to sustaining growth in productivity.

Farmers have been trying to diversify into

vegetables, fruit trees, and fish cultivation but

without much success because of the lack of


The current level of physical infrastructure is

inadequate to support potential increases in

agricultural production. Two-thirds of the farms

have no access to drying areas; most of the crop is

sun-dried. Storage space is about 1 million m 3 or

67% of the total needed. Transportation for

moving the crop to market is inadequate. Energy

is also in short supply. Although electricity is

available in most provinces, most rural

households do not have access to it.

Production opportunities

The increased production of rice and productivity

of rice-based farming systems remain the

country’s primary goals. Studies in the Mekong

River Delta have focused on various rice-based

farming systems models: rice-fish integrated with

fruit trees, rice-shrimp in saline areas, rice-fish in

deepwater areas, and rice–cash crops in the

remaining small amount of floating-rice area.

104 Rice almanac



Index (1966 = 100)











Calorie share

Protein share




1966 1971 1976 1981 1986 1991 1996 1999

Share of calories and protein from rice, 1966-99


1966 1971 1976 1981 1986 1991 1996 2000

Indices of rice production, area, and yield, 1966-2000








1966 1971 1976 1981 1986 1991 1996 1999

Per capita production (paddy terms), 1966-99















1966 1971 1976 1981 1986 1991 1996 1999

Net trade status, 1966-99

Basic statistics, Vietnam

1985 1990 1995 1998 1999 2000


Area harvested (ha) 5,703,900 6,027,700 6,765,600 7,362,700 7,648,100 7,654,900

Yield (t/ha) 2.8 3.2 3.7 4.0 4.1 4.3

Production (t) 15,874,800 19,225,104 24,963,700 29,145,500 31,393,800 32,554,000

Rice imports (t) 336,100 1,900 11,000 1,300 5,200 na

Paddy imports (t) na na na na na na

Rice exports (t) 59,400 1,624,000 1,988,000 3,700,000 4,600,000 na

Paddy exports (t) na na na na na


Population, total (×10 3 ) 59,898 66,689 73,866 77,562 78,705 na

Population, agriculture (×10 3 ) 43,275 47,546 51,232 52,869 53,330 na

Agricultural area (×10 3 ha) 6,750 6,726 7,085 7,892 na na

Irrigated agricultural area (×10 3 ha) 2,500 2,900 3,000 3,000 na na

Total fertilizer consumption (t) 385,600 544,484 1,214,000 1,947,400 na na

Tractors used in agric. (no.) 31,620 25,086 97,817 122,958 na na

Source: FAOSTAT online database.

Rice around the world 105


General information

• GNI per capita PPP$, 2000: 6,320

• Internal renewable water resources: 110 km 3

• Incoming water flow: 69 km 3

• Main food consumed: rice, sugar and honey,

oil and fat, meat, nuts

Rice consumption, 1999: 100.8 kg milled

rice per person per year

Production season

Planting Harvesting

North & Central, May-Jul Nov-Dec

major season

North & Central, Dec-Jan May-Jun

minor season

South, major season Sep-Nov Mar-May

South, minor season Apr-May Aug-Sep

Thailand lies between 5° and 21° N latitude

and between 97° and 106° E longitude. It

is a peninsular country in Southeast Asia

sharing boundaries with Myanmar in the west,

Lao PDR and Cambodia in the northeast, and

Malaysia in the south. The South China Sea

touches the east coast, while the Indian Ocean

and Andaman Sea border the west coast. Thailand

has a land area of 51 million ha, of which onethird

is cultivated for annual crops and about 7%

is under permanent crops.

Thailand is in AEZ 2, characterized as warm

subhumid tropics. Four seasons are recognized:

southwest monsoon from May through

September, a transition period from the southwest

to the northeast monsoon during October, the

northeast monsoon from November through

February, and a premonsoon hot season during

March and April.

Temperatures in the Central Plain during the

rainy season (May to November) average 27 °C,

with only 8–10 °C between the daily minimum

and maximum. There is a brief cool period

(December and January) with temperatures as low

as 2–3 °C in the northern highlands.

Rapid economic growth in nonagricultural

sectors over the two decades prior to the financial

crisis in 1997 greatly reduced the relative

importance of agriculture as a contributor to the

gross domestic product and export earnings. But

agriculture is still the dominant economic activity

in rural Thailand and is now recognized as a

critical sector to cushion the adverse effect of the

financial crisis. The population was 60.9 million

106 Rice almanac

in 1999 and grew at 0.9%/yr during the 1990s.

Despite the rapid transformation to an

industrialized economy, 78% of the population is

still rural. The average rural person has a low

level of schooling because most of the highly

educated people migrate to cities in search of

better living conditions.

The GDP was estimated at US$111 billion in

1998, of which only 11% originates from agricultural

activities. However, agriculture employs

nearly 56% of the total labor force, which shows

the large disparity in the productivity of labor

between agriculture and nonagricultural sectors.

The agricultural labor force grew by only 3.4%

during the 1990s vis-à-vis a 17% increase in the

total labor force.

Recent developments in the rice sector

Rice is the most important crop of the country.

Even though declining in relative importance, it

still occupies about 55% of the total arable land.

Rice farmers in the northeast, the main ricegrowing

region and the home of the famous

Jasmine rice, are generally subsistence farmers,

selling only their excess production. The main

surplus production is from the central region and

the north, where the average farm size is three

times larger than in the northeast, and the

production environment is favorable. Rice is the

staple food of the entire population regardless of

income. The average annual per capita consumption

is 100.8 kg of milled rice, which has been

declining since the mid-1980s.

The rice planted area grew rapidly from 6.9

million ha in 1968 to 9.8 million ha in 1988, and

since then has fluctuated between 9.0 and 10.0

million ha depending on the relative price of rice

in the world market. Rice production increased

from 12.4 to 21.2 million t during the first two

decades of the Green Revolution. Rice yield

increased relatively slowly compared with that in

other Asian countries, from 1.79 t/ha in 1968 to

2.15 t/ha in 1988, because of the predominance of

the rainfed rice ecosystem and farmers’

preference to grow high-quality, low-yielding

traditional varieties that fetch a premium price in

the domestic and the world market. Since 1988,

rice production and yield have increased very

little. The present rice yield of 2.33 t/ha is one of

the lowest in the world. However, farm

mechanization has spread widely since the mid-

1980s, which has led to a rapid increase in labor

productivity and helped sustain the profitability of

rice farming and its competitiveness in the world


Thailand is the major rice exporter in the

world market, currently exporting about 6.5

million t of milled rice per year. The exports

continue to grow despite the stagnation in

domestic production because of the declining

trend in the domestic demand for rice. Thailand

has a reputation for high-qu